Method and a device for preparing a job of two ophthalmic lenses belonging to the same pair of eyeglasses for mounting

ABSTRACT

Method of automatically preparing an ophthalmic lens for mounting, includes the following steps:
         automatically measuring centering characteristics of the lens;   blocking the lens on cutting-out elements;   feeling the lens; and   cutting out the lens,   wherein the lenses are treated together in pairs of lenses belonging to the same jobs, with the following consecutive steps being performed:   measuring and feeling both lenses of the job; then   reconciling the detected centering characteristics and the feeler information for both lenses of the job taken together, so that as a function of the result of this reconciliation, the job is confirmed or refused, and then if the job is confirmed, cutting both lenses of the job to shape, or if the job is refused, stopping the preparation of the lenses of the job.

BACKGROUND OF THE INVENTION

The present invention relates in general to mounting ophthalmic lensesof a pair of correcting eyeglasses in a frame, and it relates moreparticularly to an automatic or assisted device for preparing the lensesof a pair of eyeglasses for mounting in the frame selected by the user.

DESCRIPTION OF THE RELATED ART

The technical portion of the work carried out by an optician consists inmounting a pair of ophthalmic lenses in or on the frame selected by theuser, in such a manner that each lens is suitably positioned facing thecorresponding eye of the user so as to perform as well as possible theoptical function for which it is designed. In order to do this, it isnecessary to perform a certain number of operations.

After the frame has been selected, the optician must begin by situatingthe position of the pupil of each eye in the frame of reference of theframe. The optician thus determines mainly two parameters that areassociated with the morphology of the user, namely the pupillarydistance and the height of the pupil relative to the frame.

For the frame itself, it is necessary to identify its shape, and this isgenerally done by means of a pattern or an apparatus specially designedto read the inner contour of the rim (i.e. the part of the frame thatgoes round the lens), or else from an electronic file that isprerecorded or supplied by the manufacturer.

From the above geometrical input data, it is necessary to cut each lensto shape. A lens is cut to shape for mounting in or on the frameselected by the future user by modifying the outline of the lens so asto match it to that of the frame and/or to the shape desired for thelens. Cutting to shape comprises an edging operation for shaping theperiphery of the lens, and depending on whether the frame is of therimmed type or of the rimless type with local clamping through fastenerholes formed in the lens, appropriately beveling and/or drilling thelens. Edging (or cutting out proper) consists in eliminating thesuperfluous peripheral portion of the ophthalmic lens in question so asto reduce its outline, which is usually initially circular, to thearbitrary outline of the rim or surround of the eyeglasses frame inquestion, or merely to the pleasing shape desired when the frame is ofthe rimless type. This edging operation is usually followed by achamfering operation which consists in dulling or chamfering the twosharp edges around the edged lens. When the frame is of the rimmed type,the chamfering is accompanied by beveling which consists in forming arib usually referred to as a bevel, generally of triangularcross-section with a top that is rounded or interrupted by acounter-bevel on the edge face of the ophthalmic lens. The bevel is forengaging in a corresponding groove, also known as a bezel, formed in therim or the surround of the eyeglasses frame in which the lens is to bemounted. When the frame is of the rimless type, the cutting out of thelens and optionally the dulling of its sharp edges (chamfering) arefollowed by appropriately drilling the lenses to enable it to be securedto the temples and to the bridge of the rimless frame. Finally, when themounting is of the type having a rim of Nylon string, the chamfering isaccompanied by grooving consisting in forming a groove in the edge faceof the lens, the groove being for receiving the mounting Nylon stringfor pressing the lens against the rigid portion of the frame.

Usually, these edging, chamfering, and beveling operations are performedin succession on a single machine tool, known as an “edger” and providedwith a set of suitable cutter/grinder bits. Drilling can be performed onthe edger which is then fitted with corresponding drill bits, or else ona separate drilling machine.

The optician must also perform a certain number of measurement and/oridentification operations on the lens itself prior to cutting out inorder to identify certain characteristics such as, for example: theoptical center if the lens is a single-vision lens or the mounting crossif the lens is a progressive lens, or the direction of the axis ofprogression and the position of the centering point if the lens is aprogressive lens. In practice, the optician marks certain characteristicpoints using a marker tip on the ophthalmic lens itself. These marks areused for securing a chuck receiver or centering-and-drive pad on thelens enabling the ophthalmic lens to be positioned correctly in theedger that is to give it the desired outline, corresponding to the shapeof the selected frame. The pad is usually stuck temporarily on the lensby means of a double-sided adhesive. This operation is commonly referredto as “centering” the lens, or by extension, “blocking” the lens,insofar as the pad can be used subsequently for blocking purposes, i.e.for preventing the lens from moving relative to the means for cutting itto shape in a geometrical configuration that is known because of thepad.

After the centering pad has been put into place, the lens fitted in thisway is then placed in the cutting-out machine where it is given theshape that corresponds to the shape of the selected frame. The centeringpad serves to define and physically to embody on the lens both ageometrical frame of reference in which characteristic points anddirections of the lens are identified, with this being necessary for thelens to be positioned properly relative to the pupil, and also cuttingout values for ensuring that these characteristic points and directionsare properly positioned in the frame. In certain circumstances, it canhappen that the first attempt at cutting out the lens does not lead tothe lens being properly mounted in the frame. The operator must thenmachine the lens again. To do this, the lens is replaced in the machineand is held stationary on its clamping shaft using the same pad, thusmaking it possible to reuse the frame of reference that was used for theinitial cutting-out operation.

Depending on the organization and the equipment available to theoptician, the above-mentioned operations can be spread over two or threedistinct workstations. Each lens being processed must therefore betransferred from one workstation to another. Inaccuracies, errors, oraccidents can then arise because of the large amount of handling. Inaddition, if the operations are performed in the context of anindustrial organization, that gives to a considerable loss of time andto high production costs. In addition, the risk of damaging theophthalmic lens increases with the amount of handling, therebyconsiderably lengthening time to delivery and further increasing costs.

Document FR 2 825 308 and its equivalent EP 1 392 472 propose optimizingthe above-specified process by automating some of the measurement andpositioning stages applied to the ophthalmic lens, thus making itpossible to determine the optical characteristics of the lens and tocontrol the stage of transporting said lens to the cutting-out stationand the cutting-out stage proper.

The device proposed therein comprises means for measuring identificationcharacteristics of said lens and means for cutting said lens to shape,enabling the outline of the lens to be brought to the desired shape.Conventionally, the cutting-out means are constituted by an edger whichhas a set of grindwheels and means for blocking and driving the lens inrotation constituted by two rotary shafts on the same axis mounted tomove axially to pinch the lens on its axis like a clamp. To enable thelens to be moved towards or away from the grindwheels while machining istaking place, the clamping and drive shafts are carried by atransversely-movable rocker (movable in pivoting or in translation).Partial automation of the process of preparing the lens is obtained by asliding reception and transfer carriage arranged to transfer theophthalmic lens through two transfers between three positions, withtransfer from a measurement position in which the ophthalmic lens ispresented to the measurement means to an intermediate position distinctfrom the measurement position, and then transfer from said intermediateposition to a cutting-out position distinct from the intermediate andmeasurement positions. The lens is transferred from its intermediateposition to the cutting-out means directly by the clamping and rotarydrive shafts of the cutting-out means, by taking advantage of theability of the rocker carrying the shafts of the edger to movetransversely.

However, when using that device, the lenses are prepared sequentially,one after the other and independently of one another. In particular, thecutting out of one lens begins without waiting, immediately once itscentering characteristics have been detected. Unfortunately, itsometimes happens that one of the lenses in a pair of lenses ends upbeing incapable of being mounted properly in the frame selected by thefuture user. If the other lens of the pair of eyeglasses has alreadybeen cut out, it is then too late to change the frame or to apply someoverall modification to the pair of eyeglasses taken as a whole, wheresuch a modification would be acceptable for the ophthalmological comfortof the user.

This leads to a relatively large number of mounting operations that areimpossible, and often to it being discovered rather late that thesituation is impossible.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method and a devicefor preparing lenses for mounting, the method and device preferablybeing automatic or assisted, and making it easier to overcome mountingdifficulties and to preserve lenses from inappropriate cutting out.

To this end, the invention provides a method of preparing ophthalmiclenses for mounting, the method comprising the following steps:

-   -   an optical measurement step for acquiring the centering        characteristics of lenses; and    -   a feeling step for acquiring geometrical data of the lenses;

in which method, the lenses are processed together in pairs of twolenses belonging to the same job, with the following steps beingperformed:

-   -   optically measuring at least one of the two lenses of the job,        and feeling at least one of the two lenses of the job; and then    -   reconciling the detected centering characteristics and the        geometrical data obtained by feeling for both of the lenses of        the job considered together.

According to an advantageous characteristic of the invention, said jobis confirmed or refused as a function of the result of said reconcilingstep.

Under such circumstances, and advantageously, if the job is confirmed,both lenses of the job are cut to shape, or if the job is refused,preparation of both lenses of the job is stopped.

Thus, the first lens of a job (i.e. a pair of lenses belonging to thesame pair of eyeglasses) is not subjected to any cutting out until thesecond lens of the same job has been measured by the measurement means,and the job has been confirmed as a whole. This taking both lenses intoconsideration in the context of belonging to a particular job servesfirstly to avoid a lens being cut to shape too early, i.e. before it hasbeen discovered that at least one of the lenses of the pair of lenses ofthe job cannot be mounted in the initially selected frame, given thethickness of the lens, and thus requiring a change of frame in favor ofa frame of type and/or shape or dimensions that are compatible with thelenses of the job. Taking the lenses into consideration in pairs withina single job also makes it possible, in certain circumstances, toovercome a situation in which it is apparently impossible to mount thelenses, either by slightly changing the centering of both lenses takentogether, so as to reposition the lenses in the frame in such a manneras to make it possible for them to be mounted in that frame while stillpreserving visual comfort for the user, or by modifying the shapes ofthe outlines desired for the two lenses after cutting out in symmetricalmanner, e.g. to improve the visual field covered or the appearance of alens.

By treating both lenses of the job together it is possible to avoidmaking any confusion between the right lens and the left lens, of thekind that might otherwise occur during processing, e.g. because of theprocessing being interrupted or because of the operator beingdistracted.

According to an advantageous characteristic of the invention, the methodincludes storing in memory information relating both to the morphologyof the user and to the shape of the selected frame, and comparing saidinformation with the centering and feeling characteristics of one and/orthe other of the two lenses of the job in order to foresee anydifficulty in mounting. If a difficulty is foreseen in mounting whenperforming the comparison, provision can then be made for modifying thethree-dimensional characteristics of the mounting (radial centering andaxial positioning) for both lenses of the same job, together.

According to another advantageous characteristic of the invention, thefeeling of said lens comprises a first feeling step prior to said lensbeing blocked, during which said lens is felt around the outline desiredfor its mounting. This makes it possible to obtain feeler informationbefore blocking and transferring the lens to the cutting-out means, inorder to be able to compare the characteristics of feeling and centeringboth lenses of the job. It is also possible, during this first stepprior to transferring the lens to the cutting-out means, to perform oneor more feeler operations on the lens of the kind that are usuallyperformed on the cutting-out means and that therefore prevent them frombeing used for cutting out. It is then possible in particular toovercome exclusively sequential processing of the lenses, it now beingpossible for cutting out to take place in parallel while another lens isbeing felt. The cutting-out means are thus made available as much aspossible for their main function of cutting out. The operator or theoptician is then free to devote attention to tasks of greater addedvalue requiring the competence of the operator, such as advisingcustomers.

According to yet another optional characteristic of the invention, thefeeling of said lens comprises a second feeling step after said lens hasbeen blocked on the cutting-out means, during which said lens is feltaround the outline desired for its mounting. It is thus possible toassociate the first step of feeling with a second step of feelingcarried out on the cutting-out means. It will be understood that afterbeing blocked on the cutting-out means, the lens might be deformedslightly and that it can therefore be preferable, for the precision ofthe measurement by feeling, to perform this second feeling operation insitu on the lens in its cutting-out configuration. Nevertheless, thefirst feeler operation performed prior to blocking and transfer to thecutting-out means remains useful, since it can make it possible todetect and possibly correct any mounting difficulties entailed by thejob.

The invention also provides a device for preparing ophthalmic lenses formounting, the device comprising:

-   -   optical measurement means suitable for acquiring centering        characteristics of the lenses; and    -   feeler means suitable for acquiring geometrical data of the        lenses; and    -   an electronic and computer system which, for processing lenses        by pairs of associated lenses belonging to the same job,        possesses means for receiving and storing the centering        characteristics and the geometrical feeling data acquired by the        measurement means and the feeler means, and calculation means        for reconciling the centering characteristics and the        geometrical data for both lenses of the job considered together.

Advantageously, the calculation means of the electronic and computersystem are designed, as a function of the result of the reconciliation,to deliver a signal confirming or refusing said job.

Advantageously, the device then comprises:

-   -   cutting-out means for cutting said lens to shape; and    -   transfer means for transferring said lens, the transfer means        being arranged to transfer said ophthalmic lens between at least        two distinct positions, including a measurement position        presenting said lens in register with the measurement means, and        a cutting-out position for cutting said lens to shape on the        cutting-out means.

The electronic and computer system is then designed:

-   -   to control the transfer means, the measurement means, and the        feeler means together so that both lenses of the job are        initially processed by the measurement means and by the feeler        means, and to receive and store from the measurement means and        the feeler means centering characteristics and feeler        information; and    -   if the job is confirmed, to control the transfer means and the        cutting-out means to proceed with cutting each of the two lenses        of the job to shape, or if the job is refused, to stop the        preparation of both lenses of the job.

DETAILED DESCRIPTION OF AN EMBODIMENT

The following description with reference to the accompanying drawings ofan embodiment given by way of non-limiting example makes it possible tounderstand clearly what the invention consists in and how it can beimplemented.

DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a diagrammatic plan view of the device of the presentinvention for automatically preparing ophthalmic lenses for mounting;

FIG. 2 is an overall perspective view of the outside of the automaticpreparation device fitted with a cover;

FIG. 3 is a view similar to FIG. 2, with an access door of the covershown open for loading lenses that are to be prepared onto reception andfirst and second transfer means, and for unloading lenses therefrom;

FIG. 4 is a perspective view of the inside of the automatic preparationdevice;

FIG. 5 is a perspective view of the carousel and the seats forming thereception and first and second transfer means;

FIG. 6 is a perspective view of a portion of the automatic preparationdevice, from which the carousel of the reception and first and secondtransfer means has been removed, revealing the clamps of the receptionand first and second transfer means, together with their actuatormechanism;

FIG. 6A is a detail view in perspective on a larger scale showing one ofthe clamp fingers of FIG. 6;

FIGS. 7 and 8 are respectively a perspective view and a plan view of themechanism for opening the clamps of FIG. 6;

FIG. 9 is a view similar to FIG. 3, two first ophthalmic lenses L1, L2(or first job) of a first pair of eyeglasses being shown loaded on thereception and first and second transfer means, so as to occupy twoloading locations that are separated from each other by two unloadinglocations;

FIG. 10 is a perspective view of the preparation device in the FIG. 9configuration, with its cover removed;

FIG. 11 is a perspective view of the preparation device in aconfiguration in which the first two lenses are ready to be heldstationary by the two clamps of the reception and first and secondtransfer means;

FIG. 12 is a perspective view of the preparation device in aconfiguration where the first lens, after a first transfer, is broughtinto a measurement position in register with measurement means forautomatically measuring the centering characteristics of the lens;

FIG. 13 is a perspective view of the preparation device in aconfiguration in which the first lens, after a second transfer, isbrought into an intermediate position in order to be felt and for itsthird transfer, in register with the feeler, gripper, and third transfermeans;

FIG. 14 is a diagrammatic side view of the lens with its associatedoptical axis and boxing axis (defined below);

FIG. 15 is a perspective view of the combined feeler, gripper, and thirdtransfer means on their own;

FIGS. 16 to 18 are cross-section views of the automatic preparationdevice of FIG. 15, the feeler, gripper, and third transfer means beingshown in a plurality of successive lens-feeling configurations;

FIG. 19 is an elevation view of the automatic preparation device inwhich the feeler, gripper, and third transfer means are in aconfiguration for feeling the first lens in order to determine theheight of a remarkable point such as the optical center of said lensrelative to the measurement means in order to enable a vertex power ofthe lens to be calculated accurately at the remarkable point inquestion;

FIG. 20 is a perspective view of the preparation device in aconfiguration in which the feeler, gripper, and third transfer means arefeeling the outline of the first lens;

FIG. 21 is a perspective view similar to FIG. 19 showing the preparationdevice in a configuration in which the feeler, gripper, and thirdtransfer means are again feeling the first lens at at least three pointsin order to determine the normal to the blocking points;

FIGS. 22 to 24 are elevation views of the automatic preparation devicewith the feeler, gripper, and third transfer means being partially insection, and being shown in three successive configurations for holdingthe first lens on a gripping and blocking axis corresponding to aremarkable axis of said lens, referred to as the boxing axis (definedbelow);

FIG. 25 is a perspective view of the preparation device in aconfiguration in which the first lens is undergoing the third transferby the feeler, gripper, and third transfer means from its intermediateposition towards the cutting-out device;

FIGS. 26 and 27 are perspective views of the preparation device insuccessive configurations of its third transfer followed by integrationof the first lens in the cutting-out device;

FIG. 28 is a perspective view of the preparation device in arelay-passing configuration, in which the first lens is held both by thefeeler, gripper, and third transfer means and by the blocking and rotarydrive means of the cutting-out device;

FIGS. 29 and 30 are respectively a perspective view and a longitudinalsection view of the first lens held between two chucks, themselves inengagement with two clamping and rotary drive shafts of the cutting-outdevice;

FIG. 31 is a perspective view of a magazine comprising a plurality ofpairs of chucks for holding lenses of different sizes and/or coatings;

FIG. 32 is a fragmentary perspective view of the turntable showing avariant of the reception and first and second transfer means with anoptional lens-centering peg;

FIG. 33 is a perspective view of the automatic preparation device in aconfiguration in which the first lens of the job, after being cut toshape and transferred in a fourth transfer is replaced by the thirdtransfer means in an intermediate position on the reception and firstand second transfer means;

FIG. 34 is a perspective view of the automatic preparation device in aconfiguration in which the first two lenses have been brought to aposition for unloading by the reception and first and second transfermeans;

FIG. 35 is a perspective view of the automatic preparation device in aconfiguration in which the reception and first and second transfer meansare ready to receive a second pair of lenses of a second job, while thefirst lens of the first pair is still being processed in the cutting-outdevice and the second lens of said first pair is being processed by themeasurement means;

FIG. 36 is a plan view of the front face of a progressive correctinglens having conventional marking formed on said lens;

FIG. 37 is a diagrammatic view of an embodiment of the device formeasuring the characteristics of a lens;

FIG. 38 is a diagrammatic front view of a frame for a pair of eyeglassesin position on the nose of a wearer;

FIGS. 39 and 40 are front views showing diagrammatically the comparisonand the combined centering of the two lenses of a given job underpreparation; and

FIG. 41 is a diagrammatic perspective view of the main components of thecutting-out means.

DETAILED DESCRIPTION OF THE INVENTION

As shown more particularly in FIGS. 1 and 2, the device 1 of the presentinvention for preparing lenses for mounting comprises a plurality ofsubassemblies mounted on a common frame:

-   -   a measurement device 5 for automatically measuring various        characteristics of lenses L1 and L2 (which may for example be        single-vision, multifocal having near or intermediate vision        segment(s) with power discontinuity, or indeed multifocal with        progressive addition of power), and in particular for measuring        local ophthalmic powers at remarkable points such as the optical        center of a single-vision lens or the far vision and near vision        reference points, and for measuring at least one identification        characteristic such as a centering, axis orientation, or        localization of reference points for near vision and far vision        of the lens;    -   a cutting-out device 6 for cutting ophthalmic lenses to shape;    -   combined reception and first and second transfer means 2        arranged to receive one or more ophthalmic lens jobs, e.g. one        job comprising two lenses L1 and L2, and to make the lenses        travel between a loading and unloading position, a measurement        position in which the ophthalmic lens is presented in register        with the measurement device 5 for measuring its identification        characteristics, and an intermediate position for being taken in        charge by the feeler, gripper, and third transfer means        described below;    -   feeler, gripper, and third transfer means 7 designed and        arranged firstly to feel each ophthalmic lens being prepared,        and secondly to grip said lens in order to transfer it from the        reception and first and second transfer means 2 to the        cutting-out device 6;    -   an electronic and computer system 100 designed to execute an        automatic processing method of the invention; and    -   a cover 20 enclosing the entire assembly in order to protect it,        and possessing a small access door 26.        Measurement Device

The measurement device 5 of the present invention performs severalmeasurement functions on various characteristics of the lens. Amongstthese various functions that are described in greater detail below,there are two main functions, one consisting in measuring the localoptical powers of the lens at remarkable points thereof, and the otherconsisting in detecting and locating centering or identificationcharacteristics of the lens in order to establish or position the lensappropriately in an overall frame of reference known to the device.

While performing its first function, the measurement device 5 operateswithout making contact, by overall mapping imaging, however that isassociated with feeler means 7, which, as explained below, feel the lensin order to provide geometrical information in combination with theoptical information delivered by the measurement device 5. In theexample described below, this feeling is performed by making contactwith the lens. Nevertheless, it will be understood that the personskilled in the art could replace that with contactless feeling operatingin an equivalent manner to obtain geometrical position information.

In addition to the embodiment described below, the measurement devicecould be of any type enabling the lens to be presented betweenillumination means and analysis means in order to obtain an overallmeasurement of one or more optical characteristics at a plurality ofpoints over the major fraction of its extent. Overall opticalmeasurements can be obtained by measuring deflection (of the Hartmann,Moiré, etc. . . . type), by interferometry, by wave propagation, etc.The user interface may then display not only the optical or referencecenter, but also maps of powers and/or axial orientations at one or moreremarkable points of the lens.

In order to understand the second centering function performed by themeasurement device 5, and more generally the difficulty solved by theinvention, it is necessary to recall that when mounting an ophthalmiclens on a frame, it is important for the visual comfort of the wearer toensure that the lens is appropriately positioned relative to the eye forwhich it serves to correct defective refraction or accommodation.

Overall, an ophthalmic lens is centered when there is overlap betweenfirstly the optical center (for single-vision lenses or multifocallenses with a power discontinuity), or the reference center (forprogressive lenses), of the ophthalmic lens as specified during design,and secondly the center of the pupil of the eye, or in other words whenthe line of sight passes through the optical center or the referencecenter of the ophthalmic lens. Centering is thus the result of bringingtogether two items of geometrico-optical data: the morphology of thewearer's pupil and the position on the lens of the optical center or thereference center. In order to perform the desired optical function, thelens must also be appropriately oriented about its optical axis.

With reference more particularly to ophthalmic lenses providingprogressive addition of power, it is known that, during fabrication, anyprogressive lens is provided with temporary identification in the formof marking based on paint, and with permanent identification in the formof etching. The temporary marking makes it easy to center the lensbefore it is mounted. After the temporary marking has been removed, thepermanent marking makes it possible, on a patient's frame, to identifythe nature of the progressive ophthalmic lens, the value of itsaddition, and also to verify or reestablish the exact centering of saidlens. It will be understood that the temporary marking is removed by theoptician before handing the eyeglasses over to a client, and that, wherenecessary, the temporary marking can be reestablished on the basis ofthe permanent etched marking which remains on the ophthalmic lens.

More precisely, as shown in FIG. 36, the temporary markingconventionally comprises:

-   -   a centering or mounting cross 11 marking the center of the far        vision zone, for positioning in register with the center of the        wearer's pupil when looking straight ahead at infinity; it        enables the power progression of the lens L1 to be positioned        vertically and horizontally relative to the eye in such a manner        that the wearer can easily find, in the manner determined by the        designer of the lens, the corrective power that is needed        whether for far vision, intermediate vision, or near vision;    -   depending on the type of lens, a central point 12 that is        situated in the range 2 millimeters (mm) to 6 mm beneath the        mounting cross 11 and that locates the “optical center” of the        lens L1; this “optical center”, for a progressive lens, is        conventionally the “prism reference” where the nominal prismatic        power of the lens L1 corresponding to the wearer's prescription        is measured;    -   a circle 13 for measuring the far vision power of the lens,        which circle is situated in the upper portion of the lens L1,        immediately above the mounting cross 11, and locates the        reference point for far vision; it is thus the location where a        frontofocometer should be positioned for measuring the far        vision power of the lens L1;    -   a circle 14 for measuring the near vision power of the lens,        which circle is situated in the lower portion of the lens L1 and        surrounds the center of the reference point or center of the        near vision zone; this center is shifted towards the nose        through 2 mm to 3 mm, and the distance between it and the        mounting cross 10 constitutes the nominal length of the        progression of the lens L1; and    -   one or more lines 15 identifying the horizontal for the lens L1        and for use in centering.

As also shown in FIG. 36, the permanent marking generally comprises:

-   -   two small circles or signs 16 located on the horizontal of the        lens L1 passing through its optical center and always situated        at 17 mm on either side of the optical center 12; these etchings        serve to find the horizontal and vertical centering of the lens;    -   a sign 17 serving to identify the brand and the exact nature of        the progressive lens (e.g. V for Varilux®) that is etched under        the small circle or nasal-side sign; and    -   a 2- or 3-digit number representing the value of the addition        (e.g. 30 or 300 for an addition of 3.00 D) which is etched under        the small circle or temporal-side sign.

It should be recalled that for multiple-focus lenses presenting one ormore lines of power discontinuity (e.g. defining a near vision zoneknown as a “segment”), these lines themselves act as permanent marks.

The device 5 for automatically measuring characteristics of anophthalmic lens L1 is shown diagrammatically in FIG. 37. This automaticmeasurement device comprises a support for the lens L1, in this case ahorizontal support constituted by the carousel forming part of thereception and first and second transfer means 2 that are describedbelow. At this point it suffices to understand that the first transfermeans are suitable for bringing the lens under examination into ameasurement position situated in register with the measurement deviceand centered on the optical axis of the measurement device, as isexplained in greater detail below. Beneath this measurement position forthe lens L1, a transparent glass plate protects the inside of thedevice. On either side of this measurement position for the lens L1, themeasurement device includes, on a mainly vertical optical axis, firstlylighting means 208 including an optical system 211 for providing a lightbeam directed towards the lens L1 in its measurement position, andsecondly analyzer means 210 for analyzing the image transmitted by thelens L1 in the measurement position.

The optical system 211 is arranged to define two possible light paths212 and 213 for said light beam, which paths are switchable, i.e. theycan be activated in alternation. In the example shown, the lightingmeans comprise at least two switchable light sources S1 and S2corresponding respectively to the two above-mentioned light paths. Inother words, when the source S1 is on, the source S2 is off, and viceversa. The two light paths 212 and 213 have a common portion 215upstream from the lens L1, which common portion is determined moreparticularly between a semireflecting oblique mirror 218 and the lensL1. The mirror marks the intersection between the two light paths. Themirror 218 may be replaced by a splitter cube or a removable mirror.

A first mask 220 forming a Hartmann matrix or the like is placed on onlyone of the paths (the path 212) at a location such that it occupies aposition that is predetermined relative to a vertical main optical axis225 of said analysis means 210. This optical axis 225 is the axis commonto certain lenses of the optical system that are centered relative tothe source S1, and of a light receiver 228 forming part of the analysismeans 210 and situated on the other side of the lens L1 in themeasurement position. The analysis means also include a frostedtranslucent screen 229 interposed perpendicularly to the optical axis225 between the lens L1 in the measurement position and said lightreceiver 228. The light receiver may be a matrix sensor or a camera withan objective lens. If the light receiver is a matrix sensor, it isassociated with an objective lens 231, and possibly also with adiaphragm that is not given in the example shown. If the light receiveris a camera, these elements are replaced by the lens system of thecamera. The ground translucent screen 229 is preferably made of glass orthe like with a ground surface. It constitutes a disk that is mounted torotate and that can be driven in rotation by a motor 235 about theoptical axis 225.

Returning to the optical system 211 associated with the sources S1 andS2, the first light source S1 of these two sources is a point lightsource suitable for providing a diverging beam that illuminates thefirst mask 220 along a first path 212 prior to being reflected on theoblique mirror 218 so as to travel along the common portion of the lightpath 215, thereby illuminating the ophthalmic lens L1. The obliquemirror 218 is at an angle of 45° relative to the optical axis 225 suchthat the beam coming from the source S1 is reflected on the mirror andis directed towards the ophthalmic lens L1. Downstream from the firstmask 220, and thus on the first light path 212, the light emitted by thesource S2 is split up into a plurality of distinct light rays, with theHartmann type first mask 220 performing its beam splitter function.

The source S1 may optionally be movable along the optical axis or anaxis perpendicular thereto, but when activated it always illuminates thefirst mask 220. The optical system also includes a collimator lens 241centered on the optical axis 225 and placed between the mirror 218 andthe measured ophthalmic lens L1. This lens 241 serves to generate aparallel light beam of size that is large, greater than that of the lensL1, and to make an image of the first mark 220 on the surface of theophthalmic lens L1.

A second light source S2 is arranged to illuminate the lens L1 in themeasurement position via the second light path 213, excluding the firstmask 220 that forms the Hartmann matrix. Light from this second lightsource passes through the semireflecting mirror 218 marking theintersection between the two light paths 212, 213. This source S2 is apoint source suitable for delivering a diverging beam directed towardsthe mirror 218. The axis of the beam generated by the source S2 isperpendicular to the beam generated by the source S1 upstream from themirror 218 and it passes through this mirror without being deflected. Itthen illuminates the ophthalmic lens L1 without being subjected to anybeam separation splitting by any splitter element of the Hartmann masktype or the like.

A second Hartmann type mask 240 or similar beam separator is placeddownstream from the ophthalmic lens L1, i.e. between the lens and theimage analysis means 210. Specifically, the mask 240 is situated underthe protective glass 203, and adjacent thereto. This second mask 240 canbe engaged and disengaged at will, under the control of the electronicand computer system 100.

In practice, the second mask can be made in the form of a transparentliquid crystal display (LCD) screen or the like, as in the exampleshown. It may also be constituted by a passive mask that is permanentand mounted to move relative to the ophthalmic lens, so as to besuitable for being moved out of the way so as to uncover at least aportion of the ophthalmic lens when said portion is to be examinedwithout the second mask, in a manner that is explained below.

Under such conditions, terms such as “engageable” and “disengageable”mean that the mask in question either does or does not perform itsfunction of splitting up the light beam upstream or downstream from thelens over all or part of the surface of the ophthalmic lens.Specifically, it will be understood that the engagement or disengagementof the mask can be performed in different manners depending on the typeof mask used.

When the mask is of the passive type, e.g. constituted by a support withone or more patterns marked on the support, such as a grid or aperforated plate, then the term “disengageable” means in particular thatthe mask can, in particular, be retracted mechanically in full or inpart, so the mask is mounted to move relative to the lens (either by themask itself being movable or by the lens being movable while the maskremains stationary) so as to enable at least a portion of thecorresponding surface of the lens to be disengaged and illuminated orread directly with the complete light beam, i.e. without said beam beingsplit up. The term “disengageable” can also mean optically bypassable,as is the case for the mask 220.

When the mask is of the active type and consists for example of adynamic display screen such as a CRT or LCD screen, then the term“disengageable” means “deactivatable”: the electronics controls thescreen so that it switches off all of its splitter patterns over atleast a zone of the screen corresponding to the zone of the lens that isto be read without the beam being split up.

In the example shown, the mask 240 is of the LCD active type, so it isdeactivatable, while the mask 220 is of the passive type (permanent) andis optically bypassable (by having two alternative light paths 212 and213). Nevertheless, in a variant, provision could be made for the mask220 that is situated between the source and the lens to be of the activetype, such as an LCD screen, suitable for being activated anddeactivated electronically, like the mask 240 situated between the lensand the translucent screen.

In operation, the measurement device as constituted in this way can takeup three states corresponding to three modes of operation:

State 1: the source S1 is activated and illuminates the lens L1 throughthe first mask 220 (this first mask thus being “activated”), the sourceS2 being off and the second mask 240 being deactivated; in other words,the first mask 220 is the only mask engaged.

State 2: the source S2 is activated and the second mask 240 isactivated, the source S1 being off (the first mask 220 thus being, so tospeak, “deactivated); the second mask 240 is thus the only mask engaged.

State 3: only the source S2 is activated, the source S1 and itsassociated mask 220 being deactivated, and the second mask 240 beingdeactivated (or retracted) at least in part; thus both masks 220 and 240are disengaged simultaneously.

In state 1, the source S1 and its associated mask 220 are activated andthey are used for correcting read error and for repositioning the marks,identifiers, or indicators (etching, marking, segments) on the frontface of the lens as seen on the screen 229 by the sensor 218, and due toprismatic deflection through the ophthalmic lens L1.

In state 2, the source S2 and its associated mask 240 are activatedtogether while the source S1 is deactivated, to perform overall analysisof one or more optical characteristics at a plurality of points over theentire extent of the lens, in order to measure said opticalcharacteristic(s) at one or more isolated remarkable points (such as thereference points for near vision and for far vision of a progressivelens, or the optical center(s) of a single-vision lens or a multifocallens having power discontinuity) or, possibly, to establish a map of theophthalmic lens L1 (in particular by measuring power and/or astigmatismat a plurality of points on the lens) and determining the optical centerof the ophthalmic lens L1 when it is of the non-progressive type.

In state 3, the source S2 is activated on its own, with both the sourceS1 and the second mask 240 being deactivated, in order to determineprinted marks, etching in relief, and segments (for bifocal and trifocallenses), which operation requires a disengaged view of the ophthalmiclens, at least locally.

The above-mentioned light sources S1 and S2 may be light-emitting diodes(LEDs) or laser diodes, preferably associated with respective opticalfibers.

There follows a description of the manner in which the measurementdevice can be used to determine a certain number of opticalcharacteristics of the ophthalmic lens L1 in the measurement position.

First Function: Identifying the Ophthalmic Lens

Before anything else, it is useful to be able to recognize the type ofophthalmic lens under analysis (single-vision, multifocal, orprogressive) in order to avoid errors. To do this, the source S2 is usedtogether with the second mask 240 forming a Hartmann matrix. Themeasurement device is in its state 2 or its state 3. The beam on thesecond light path 213 is transformed by the second mask 240 into aplurality of individual fine rays corresponding to the configuration ofthe mask. Each of these rays strikes the front face of the lens L1parallel to the optical axis 225, i.e. generally perpendicularly to themidplane of the ophthalmic lens L1 (and thus specifically vertically,since the ophthalmic lens L1 is held horizontally by the reception andfirst and second transfer means 2, as explained below). These rays aredeflected by the ophthalmic lens L1 and they are displayed in the formof light spots on the rotating translucent screen 229. The screen isimaged on the matrix sensor associated with the afocal system or on thesensor of the camera, and the spots are analyzed by an electronic andcomputer processor system (associated with or integrated in theelectronic and computer system 100) in order to determine their offsets.

If the lens is of the single-focus type, the offsets of the points ofthe mask (i.e. the light spots that appear on the translucent screen)after being deflected by the lens progress radially from the centertowards the periphery compared with the positions of the same pointswhen no ophthalmic lens is present on the optical axis of themeasurement device. The positions of the points of the Hartmann mask onthe screen when no lens is present in front of the measurement deviceare measured during a calibration stage.

For a converging lens, the spots are offset towards the optical axis, byan amount that increases with increasing power of the ophthalmic lens tobe measured.

When the lens under analysis is progressive, the distribution of thepoints does not present axial symmetry.

Consequently, measuring displacement in this way enables the type of thelens to be determined.

Other means and methods for determining lens type are well known to theperson skilled in the art and could be used in the context of thepresent invention instead of the example given above.

Second function: Determining the Line of Progression of a ProgressiveLens

In the measurement conditions specified above (state 2), it is foundthat for a progressive lens, the offset of the points varies along aline referred to as the “progression line”. In order to determine thisprogression line, calculation is used to determine the direction of thepower gradient by calculating power at different points of the lens,e.g. using the method specified below. This direction is the progressionline. It is thus possible to measure and calculate the orientation ofthe progression line which is an important characteristic of aprogressive lens. It should be observed that these calculations arecarried out on the basis of two data series, firstly the configurationof the points of the Hartmann second mask 240 on the translucent screenwhen no ophthalmic lens is present on the optical axis of themeasurement device, and secondly the corresponding configuration of thesame points when it results from the set of deflections imparted to therays by the ophthalmic lens L1.

Third Function: Determining the Optical Center for a Non-ProgressiveLens

If the ophthalmic lens L1 has been identified as being of thesingle-vision type, it is easy to determine the position of the opticalcenter of the lens. With the device still in its state 2, it suffices tocompare the points of the reference mask (appearing on the translucentscreen 229 when no lens is present on the optical axis of themeasurement device) with the corresponding points of the mask viewed onthe translucent screen after deflection by the lens. In principle, thepoint of the second mask 240 that is not deflected corresponds to theposition of the optical center. Since in general there is not any raythat is subjected to no deflection, it is necessary to performinterpolation from the least-deflected rays, e.g. by applying the leastsquares method on a polynomial model.

Fourth Function: Calculating the Power and the Astigmatism of theOphthalmic Lens

For a single-vision lens, it is known that the distance between thefocus and the rear face of the ophthalmic lens represents the vertexpower. The position of the rear face of the ophthalmic lens L1 is givena posteriori by feeling using feeler, gripper, and third transfer means7, as explained more fully below. In order to determine the focus, thedevice remains in its state 2, and use is made again of the image on thetranslucent screen of the second mask 240 that forms a Hartmann matrix.For this purpose, comparisons are made between the positions ofcorresponding points between the calibration image (taken before puttingthe ophthalmic lens in place) and the image after the ophthalmic lenshas been interposed. Given the distance between the mask 240 and thescreen 229 (known by construction), the deflection angle of the lightrays coming from the beam separation performed by the mask 240 arededuced by calculation.

For a plurality of adjacent points, comparisons are made between thepositions and the directions of the light rays, thus making it possibleto calculate the position of the focus on the optical axis (and thus itspower which is the reciprocal of the distance between the focus and theophthalmic lens) and the astigmatism of the ophthalmic lens (the valueand the axis of the astigmatism) if there is any astigmatism. Thesemeasurements are local and can be repeated over different zones of theophthalmic lens, thus making it possible to obtain a map of the powersof the ophthalmic lens.

Fifth Function: Determining the Center Point and the Horizontal Axis ofa Progressive Lens

It is known that for any point of an ophthalmic lens it is possible toassume that the front face and the rear face of the lens form an anglethat can be treated as a prism. Furthermore, in a progressive lens,addition is defined as being the difference between the maximum powerand the minimum power of the ophthalmic lens.

In general, the reference point of the prism is defined as being thepoint where the prism of the ophthalmic lens is equal to the prescribedprism. On a progressive lens, the prism reference point (PRP) can betreated as being the optical center of a single-vision lens (and byabuse of language it is sometimes called the optical center) and it issituated at the center of a line between two reference marks etched onthe front face of the lens. As a general rule, this point is alsoidentified by a specially printed mark.

In any event, identifying the prism reference point or any otherremarkable point suitable for use in centering the ophthalmic lens L1when said lens is a progressive lens, is performed in state 3 byilluminating the lens L1 from the light source S2, i.e. avoiding theHartmann first mask 220. The image transmitted by the ophthalmic lens L1appears on the translucent glass 229 and is perceived by the lightreceiver 228. Reading is accompanied by suitable image processing inorder to identify the etched marks or the other marking and in order todetermine the positions thereof in a known fixed frame of reference ofthe electronic and computer system 100. This viewing of the etched orother marks and determination of the prism reference point then makes itpossible to determine the centering point of the progressive lens(mounting cross) which needs to be made to coincide with the position ofthe center of the pupil of the wearer's eye and the horizontal axis thatgives the orientation of the ophthalmic lens in the frame.

Sixth Function: Determining the Position of the Segment for a BifocalLens

The source S2 is used again without a mask (state 3 of the measurementdevice) serving to view the image of the ophthalmic lens L1 on thetranslucent screen. Appropriate image processing enables variations inlight intensity on the screen to be observed better and consequentlymakes it possible to obtain a sharp outline for the boundary of thesegment, and thus to determine its position accurately.

Seventh Function: Determining the Shape and the Dimensions of theOphthalmic Lens

These characteristics are determined by illuminating the ophthalmic lensfrom the source S2 without the Hartmann mask (state 3 of the measurementdevice) and by performing suitable image processing in order todistinguish better the outlines of the ophthalmic lens. Prior to cuttingout, the ophthalmic lens is generally circular and this analysis servesmainly to determine its diameter. Nevertheless, it can happen that theophthalmic lens already has a shape that is close to the shape of theframe for which it is intended. The image processing serves to determinethe shape and the dimensions of a non-circular ophthalmic lens.Determining the shape and the dimensions of the ophthalmic lens make itpossible to verify whether it is large enough to be held in the selectedframe or shape.

Eighth Function: Correcting Reading Errors Due to Prismatic DeflectionsInduced by the Ophthalmic Lens Under Measurement

It should be observed that for all of the above-mentioned parametersthat are acquired by illuminating the ophthalmic lens using the sourceS2 alone, i.e. excluding the two Hartmann masks 220 and 240, it ispossible to reprocess the measurements in order to transfer thepositions of the marking etching or segment read on the translucentscreen onto the front face of the ophthalmic lens. The source S2 makesit possible to see the marking, etching, or segment, but does not makeit possible to determine the real positions thereof on the front face ofthe ophthalmic lens. In contrast, the source S1 associated with thefirst matrix 220 does enable the precise positions of said elements onthe front face of the ophthalmic lens to be calculated from theinformation acquired with S2.

The procedure is as follows. It is assumed that consideration is beinggiven to a light spot A on the translucent screen 220, corresponding toone of the holes in the Hartmann mask. The corresponding light raystrikes the front face of the ophthalmic lens L1 at A′. In a first step,the source S2 is switched on and the corresponding image that appears onthe translucent screen is stored. Then, the source S1 is switched on andthe source S2 is switched off. The image of the Hartmann mask thenappears on the translucent screen 229. By construction, the height ofeach hole in the Hartmann mask (distance of the hole from the opticalaxis 225) is known. Consequently, for a given ray, the height of thecorresponding ray at its point of entry on the front face of theophthalmic lens L1 is known. I.e. the height of the point A′corresponding to the point A is known. Consequently, it is possible toapply a correction to the point A so as to determine A′. It is thuspossible to find the position on the lens itself, of any marking read onthe translucent screen, and thus improve the accuracy of suchmeasurement. In other words, the use of the Hartmann mask 220 inassociation with the light source S1 (said Hartmann mask being placedupstream from the ophthalmic lens L1), makes it possible to improve allof the measurements that are carried out by illuminating the lens usinga source S2 that follows a light path excluding said mask.

Ninth Function: Correcting Errors in Measuring Powers on All Types ofLens and in Centering and Finding the Axis of Single-Vision Lenses

The two masks 220 and 240 situated on opposite sides of the lens make itpossible in combination to correct at least in part errors due to faultypositioning of the lens and concerning centering, locating theorientation of the axis, and measuring power.

For various reasons, e.g. faulty positioning of the lens for measurementon the support turntable 30 when changing lens, or misalignment of themeasurement device relative to the turntable 30 supporting the lens formeasurement, it can happen that the lens present in register with themeasurement device has its axis at an angle that is not negligiblerelative to the main axis 225 of the measurement device. Such lack ofhorizontally in the positioning of the lens for measurement leads tooptical aberrations in the wave front in the vicinity of the point whereit is desired to make a measurement (which may be the optical center orany other remarkable point of the lens on which it is desired to measurean optical characteristic) and can also lead to the ray passing throughthis point being offset. These optical aberrations or offsets of therays at the point of interest falsify the measurements of the opticalcharacteristics, and in particular can falsify the measurements ofpowers and of local optical axes of the lens when the lens is of anytype and in particular when the lens presents progressive powervariation, and can also falsify the measurements of the position of theoptical center and the orientation of the main axis of astigmatism whenthe lens is of the single-vision type.

In particular, it can thus happen that an error e₁ is made in measuringthe position of the optical center of a single-vision lens, which erroris approximately equal to the following product:e₁=i.d₁where i is the angle of inclination of the optical axis of the lensrelative to the main axis of the measurement device, i.e. specificallyrelative to the vertical, and where d₁ is the distance between the mainimage plane and the convex front face of the lens (when said face is thetop face looking towards the sources S1 and S2, as in the exampledescribed).

Because of the possibilities made available by combining two beamsplitter masks that are situated on either side of the lens, it ispossible to measure this error and thus correct it at least in part. Theprocedure is as follows.

The optical center is measured in application of the third functiondescribed above, using state 2 of the device, and with only the secondmask 240 being engaged.

Thereafter, the offset e₂ at said point that results from the error ofinclination i of the lens to which a ray might have been subjected ismeasured using state 1 of the device, with only the first mask 220 beingengaged.

If this offset is zero, then it is deduced that the lens is properlypositioned, i.e. properly horizontal (zero inclination, i=0).

Otherwise, the angle of inclination i of the optical axis of the lensunder measurement is calculated approximately by using the followingformula:i≈e₂/d₂where e₂ is the measured offset, and d₂ is the mean distance dependingon the power of the lens under measurement between the main object planeand the main image plane of the lens under measurement.

A correction equal to the error e₁≈i.d_(1m) is then applied to themeasured position for the optical center, where d_(1m) is an averagedestimate, depending in particular on the power of the lens, and thedistance between the main image plane and the convex front face of thelens (when said face is the top face facing the sources S1 and S2, as inthis example).

Cutting-Out Device

The cutting-out device 6 can be made in the form of any cutting-outmachine or machine for removing material that is adapted to changing theoutline of the ophthalmic lens so as to match that of the rim of aselected frame. By way of example, such a machine may be constituted byan edger cutting and/or grinding mechanically, a laser cutting machine,a water jet cutting machine, etc.

Specifically, and as in the example shown, it may be an edger of thekind conventionally used for cutting out ophthalmic lenses foreyeglasses that are made of mineral or plastics material. Such an edgercomprises mainly, on a frame, a machining station which is fitted withone or more edging cutters and grindwheels and one or more chamferinggrindwheels mounted to rotate about an axis under the control of a drivemotor, and a carriage which is fitted parallel to the axis of saidgrindwheels with two coaxial clamping and rotary drive shafts for thelens. These shafts are suitable for holding the lens for treatmentaxially and they are mounted to rotate under the control of a drivemotor.

The carriage is mounted to move on the frame, but transversely relativeto the axis of the grindwheels, under the control of thrust means urgingit towards said axis, and secondly axially parallel to the axis of saidgrindwheels, under the control of suitable control means.

For transverse movement relative to the axis of the grindwheels, whichis necessary in order to press the ophthalmic lens for treatment againstthem, the carriage may, for example, be mounted to pivot on a shaftparallel to said axis (the carriage can then be referred to as a“rocker”) or it may be mounted to move in translation perpendicularlythereto.

More precisely, in the example shown diagrammatically in FIG. 41, thecutting-out device 6 comprises, in conventional manner, an edger 610.Specifically, the edger carries firstly a rocker 611 mounted to pivotfreely about a first axis A1, in practice a horizontal axis, on a frame601 associated with the main structure of the preparation device, andwhich, for supporting and holding an ophthalmic lens such as L1 that isto be machined, is fitted with two clamping and drive shafts 612, 613that are in line with each other along a second axis A2 parallel to thefirst axis A1 and suitable driven in rotation by a motor (likewise notshown), and secondly at least one grindwheel 614 which is constrained torotate on a third axis A3 parallel to the first axis A1 and which isalso suitably driven in rotation by a motor that is not shown. Forsimplification purposes, the axes A1, A2, and A3 are represented bychain-dotted lines in FIG. 41.

In practice, the edger 610 has a set comprising a plurality ofgrindwheels such as 614 mounted one after another on the third axis A3in order to blank out and finish the ophthalmic lens L1 that is to bemachined, the entire assembly being carried by a carriage, likewise notshown, mounted to move in translation along the first axis A1. Thesevarious grindwheels are each adapted to the material of the lens beingcut out and to the type of operation that is to be performed (blankingout, finishing, grooving, etc.).

The grindwheel 614 (or more precisely the entire set of grindwheels) ismovable in translation along the axis A3 and is controlled in thismovement by motor drive means that are not shown.

In practice the edger is automatic, commonly said to be numericallycontrolled, with the machine 610 of the invention further including alink 616 that is hinged at one end to the frame about the same firstaxis A1 as the rocker 611, and at its other end hinged to a nut 617about a fourth axis A4 parallel to the first axis A1. The nut 617 ismounted to move along a fifth axis A5, commonly referred to as therestitution axis, extending perpendicularly to the first axis A1, therebeing a contact sensor 618 acting between the link 616 and the rocker611. The pivot angle of the rocker 611 about the axis A1 relative to thehorizontal is referenced T. This angle T is linearly associated with thevertical movement in translation of the nut 617 along the axis A5, whichmovement is written R.

For example, as shown in FIG. 41, the nut 617 is a tapped nut in screwengagement with a threaded rod 638 that is in alignment on the fifthaxis A5 and is rotated by a motor 619.

By way of example, the contact sensor 618 is constituted by a Halleffect cell.

When the ophthalmic lens for machining, appropriately clamped betweenthe two shafts 612 and 613 is brought into contact with the grindwheel614, it has material removed selectively therefrom until the rocker 611comes into abutment against the link 616 by bearing against the contactsensor 618, which duly detects the abutment.

In a variant, provision could be made for the rocker 611 to be hingeddirectly to the nut 617 mounted to move along the restitution axis A5. Astrain gauge is associated with the rocker to measure the machiningadvance force applied to the lens. This thus measures continuouslythroughout machining the machining advance force applied to the lens,and then the progress of the nut 617 and thus of the rocker 611 iscontrolled so that this force remains below a maximum setpoint value.For each lens, this setpoint value is adapted to the material and to theshape of the lens.

In any event, in order to machine the ophthalmic lens L1 around a givenoutline, it thus suffices firstly to move the nut 617 accordingly alongthe fifth axis A5 under the control of the motor 619, and secondly tocause the shafts 612, 613 to pivot together about the second axis A2, inpractice under the control of the motor that controls them, so that allof the points of the outline of the ophthalmic lens L1 are involved insuccession.

The electronic and computer system 100 is appropriately programmed forthis purpose to coordinate these two operations.

The above dispositions are well known in themselves and they do not formpart of the present invention proper, so they are not described ingreater detail herein.

Combined Reception and First and Second Transfer Means

The reception and first and second transfer means 2 are in the form of acarousel which is described more particularly with reference to FIGS. 4to 8 and which comprises:

-   -   a loading and unloading turntable 30 mounted on the common frame        to turn under the control of control means (specifically an        electric motor that is not shown) itself controlled by the        electronic and computer system 100, about an axis of rotation        that passes substantially through the center of the turntable,        perpendicularly to its plane;    -   a support structure 31 secured to the common frame;    -   reception seats 34, 35 on which the lenses L1 and L2 are to rest        while being loaded onto the turntable 30;    -   at least three loading places 36 to 38 and at least four        unloading places 41 to 44 on the loading and unloading turntable        30; and    -   means 32 for preventing lenses L1 and L2 loaded on the turntable        30 at the loading places 36 to 38 from moving.

In the example shown, the loading places 36 to 38 are constituted by acorresponding number of notches or recesses. These three notches 36 to38 are identical, each presenting a shape that is substantially circularand of diameter slightly greater than the standard diameter (about 70mm) of lenses L1 and L2 for cutting to shape. The three notches arearranged to open out into the periphery of the loading and unloadingturntable 30. These openings give access to at least two seats 34, 35 onwhich the lenses for cutting to shape rest. Clamps 32 constituting themeans for preventing the lenses from moving (FIGS. 6 to 8) are hinged inregister with the loading places 36 to 38.

As shown in the figures, and in particular in FIG. 5 which is a detailview of the turntable 30, the four unloading places 41 to 44 areconstituted by hollows or cups formed in the surface of the turntable30. These hollows or depressions are circular in shape and of diameterthat is always greater than the diameter of the lenses L1 and L2 afterthey have been cut to shape.

Substantially radial slots 45 are formed from the center of eachunloading hollow 41 to 44 to the peripheral edge of the turntable 30into which the slots open out. These slots are for enabling the lensesto be handled after being cut to shape by the third and fourth transfermeans, as explained below.

Each slot 45 is arranged to form a slideway for receiving an associatedtongue 49 that is mounted in the slot 45 with which it is associated toslide between an outer position overlapping the corresponding slot 45,as illustrated by the position of the tongue 49 associated with theunloading recess 42 in FIG. 5, and a retracted inner position in whichit is retracted towards the center of the turntable 30 under theturntable 30, as illustrated by the position of the tongue 49 associatedwith the unloading recess 41 in FIG. 5. Each tongue 49 is connected to areturn spring situated under the turntable 30 (not visible in thefigures) and urging it towards the outer position in which it overlapsthe slot 45.

In a variant, provision could also be made for the overlap tongues 49 tobe mounted on the turntable of the carousel to pivot between a retractedposition and a position overlapping each corresponding slot. Thepivoting of each tongue could then advantageously by controlled by thesame mechanism as is used for actuating the clamps.

Alternatively, provision could also be made for the hollows or cups 41to 44 to be entirely closed and to present no openings so as to bewatertight.

In any event, the hollows or cups 41 to 44 present respective closuretongues or else they are closed, and it can be seen that they arearranged in such a manner as to collect the drops of lubricant comingfrom each lens after it has been cut to shape. This avoids wetting thecomponent parts that might be subject corrosion, or the electronics, orthe parts that are required to be very clean as applies in particular tothe optical measurement device 5.

In preferred manner, a first loading place 36 is diametrically oppositethe other two loading places 37 and 38, themselves situated side byside. The four unloading places 41 to 44 are grouped together in pairs.Thus, a first pair of unloading places 41, 42 is interposed between thetwo loading places 36, 37, while the other two unloading places 43, 44are situated between the loading places 36 and 38.

This provides a loading and unloading turntable 30 that is very compact,serving to maximize the number of pairs of lenses that can be processedin a small volume. The loading places and the unloading places areregularly distributed around the periphery of the turntable and they allhave substantially the same area.

The means 32 for holding the lenses in place comprise clamps 46 to 48,each situated vertically above a corresponding loading place 36 to 38.Each of these clamps comprises two branches 50 and 51 with their roots53 hinged on a hub 54 and with their free ends 55 being provided withgenerally V-shaped hinged fingers 56.

The hub 54 is constrained to rotate with the loading and unloadingturntable 30 in such a manner that the clamps 46 to 48 are rotatedsimultaneously with the turntable. Each clamp thus remains in registerwith a respective one of the loading places 36 to 38.

Each of the clamps 46 to 48 is urged towards a closed position by arespective resilient element such as a return spring 57 placed betweenthe roots 53 of the two branches 50, 51 of each clamp.

Furthermore, the three clamps 46 to 48 are driven into an open positionin which they can take hold of a lens by a special drive mechanism 58.As can be seen more particularly in FIGS. 7 and 8, the drive mechanism58 consists in a system of cogwheels and belts serving to controlrotation of three heads 60, each situated in the vicinity of arespective clamp root 53. Each of these heads is designed to co-operatein alternation like a screwdriver with complementary actuator forks 61,each carried by a respective one of the clamps 46 to 48.

The drive mechanism 58 is mounted stationary on the structure 31 andtherefore does not turn with the turntable 30 and the hub 54. Itcomprises three assemblies, each constituted by a drive pulley 62, acogwheel 63, and a belt 64 tensioned between the pulley and thecogwheel. The cogwheel 63 carries the finger 60 that is itself situatedon the circular path of the fork 61 with which it co-operates.

Thus, when the loading and unloading turntable 30 and the clamps 46 to48 are brought into a reference position, also referred to as theloading/unloading position, the forks 61 are brought into co-operationwith the heads 60, each of the heads 60 penetrating into turn in thecorresponding fork 61. The drive pulleys 62 are then caused to turn soas to turn the cogwheels 63 and thus the forks 61 engaged with the heads60, enabling the clamps 46 to 48 to be opened by moving the branches 50,51 apart against the springs 53.

In order to simplify the mechanism, the roots 53 of the branches 50, 51of each of the clamps 46 to 48 co-operate mutually by gearing. For thispurpose, and as can be seen in FIG. 8, each of the roots 53 possesses atoothed arc 65 facing towards the adjacent root 53. It thus suffices forthe fork 61 to be carried by only one of the two branches 50 and 51 of aclamp for both of the branches to be moved and for the clamp to beopened.

It will thus be understood that with each of the clamps 46 to 48 beingurged towards the closed position by its spring 57, the actuator fork 61that enables the clamp to be opened is arranged to come into engagementwith a corresponding complementary actuator head 60 of the drivemechanism when the carousel 2 is in a determined position, and only whenit is in that position. It should be observed that the drive mechanism60 to 65 is not on board the carousel 2, but on the contrary it isstationary, being associated with the structure of the device. As aresult, only the on-board clamps 46 to 48 revolve with the carousel,thereby avoiding any moving electrical connection. In addition, thecarousel is lighter in weight, thus presenting lower inertia and thusbeing easier to control accurately in turning.

Furthermore, each of the fingers 56 of the clamps 46 to 48 presents aninside face 56.1 for engaging a lens, which face is curved in shape andoccupies a substantially vertical plane. The height of this grippingface of each finger is sufficient relative to the thickness of thelenses to be capable of taking hold of said lenses firmly via their edgefaces. For example, provision could be made for a height lying in therange 10 mm to 20 mm that is suitable for all prescriptions. The bottomflanks 68 of the fingers 56 are provided with crenellations 69. Inaddition, and as can be seen in FIG. 6A, the projecting portions 68.1 ofthe crenellations of the bottom flank 68 of each finger 56 projectshorizontally inwards so as to form a wedge-shaped scraper tooth 68.1serving to receive the lens when the clamps tighten.

As shown more particularly in FIGS. 4 and 6, each of the seats 34, 35possesses a top face 70 facing towards the loading and unloadingturntable 30. While being loaded on the turntable 30, the lenses forcutting to shape are placed on the top face 70 of each of the two seats34, 35. Advantageously, set back from the top face 70 of each seat,there is provided a central groove 71 arranged in such a manner that thetop face 70 is divided into two bearing zones, an outer zone 72 and aninner zone 73, for bearing against the lenses on either side of thecentral groove 71. This central groove is curved in shape, with itscenter of curvature corresponding substantially to the center ofrotation of the hub 54 carrying the clamps 46 and 48 and the turntable30. The depth of the central groove 71 is adapted so that at least someof the crenellations 69 move inside the groove during closure andturning of the clamps. Advantageously, the depth of the groove 71 issubstantially equal to one-third of the height of the fingers 56 of theclamps 46 to 48. Thus, during closure, the clamps 46 to 48 come intoengagement with the edge face of the lens over its entire thickness andthe side faces of the fingers 56 even project downwards, i.e. towardsthe bottom of the groove 71. This disposition makes it possible toensure that the lens is held securely and firmly, even when the lens isof small thickness.

In order to ensure better that the lens is seated stably andhorizontally, in particular when it is of small size like the right-handlens in FIG. 6, two beads 75, 76 are formed in the bottom of the centralgroove 71. Each of the beads 75, 76 possesses a top edge situated in thesame plane as the top face 70, and thus serves to provide a planebearing surface for the lens in addition to the bearing zones 72, 73.These are mutually spaced apart in the form of circular arcs so as toco-operate with the hollow portions in relief of the crenellations 69 ofthe bottom face 68 of the fingers 56 during closure of the clamps 46 to48. In a variant, these beads may also have a second function: that ofguiding the movement of the fingers 56 during closure and opening of theclamps 46 to 48.

In addition, the seats 34, 35 are mounted on the structure 31 in such amanner as to be vertically movable, like an elevator, between a highposition in which the top faces 70 of the seats are in the vicinity ofthe fingers 56 of the clamps 46 to 48, and a low position in which thetop faces of the seats are spaced apart from said fingers 56. Thus, theseats 34 and 35 are in a high position when the lenses are loaded ontothe turntable 30 in order to be held in place by the clamps, and theyare in a low position when the lenses are taken by the clamps so as tobe moved to the following station, i.e. the measurement device 5. In thelow position, the seats 34 and 35 are retracted to allow the clamps andthe lenses to move freely.

Preferably, the measurement device 5 and the feeler, gripper, and thirdtransfer means 7 are situated side by side in a position diametricallyopposite the access door 26. The measurement device 5 is situated atleast in part vertically over the path followed by the loading spaces 36to 38 and unloading spaces 41 to 44 so that the lenses L1, L2 remaincarried by the loading and unloading turntable 30 while theircharacteristics are being determined.

In addition, the cutting-out device 6 is placed adjacent to the loadingand unloading turntable 30, and the feeler, gripper, and third transfermeans 7 are interposed between the measurement device 5 and thecutting-out device 6.

Combined Feeler, Gripper, and Third Transfer Means

After certain characteristics of the lens L1 have been determined bymeans of the measurement device 5, in particular by implementing themethod described at the beginning of the present description, theloading and unloading turntable 30 is again turned so as to subject thelens L1 to a second transfer, bringing it into register with the feeler,gripper, and third transfer means 7 (FIG. 13). The lens L1 is then in aso-called “intermediate” position.

In order to identify the lens L1 correctly, it is necessary to add tothe preceding measurement by feeling the lens. As a general rule, it isof interest to know the height e of the lens relative to the measurementdevice 5, and also to an axis referred to below as the boxing axis,written AB and defined below with reference to FIG. 14.

It is recalled that the optical center CO of the lens is the point whereit presents no prism deforming the image. The optical axis AO is theaxis perpendicular to the plane of the lens passing through the opticalcenter CO. The height e is calculated by feeling the lens at thelocation of the optical center CO.

The gripping and blocking point of the lens where blocking is to beperformed is also defined. This point is selected to coincide with apoint referred to as the boxing center CB, well known to the personskilled in the art, and constituted by the point of intersection of thediagonals of the horizontal rectangle in which the shape of the outlinedesired for the lens after being cut to shape is defined in use(defining the horizontal). This boxing center is determined by themeasurement device 5 as a function of the measured identificationcharacteristics of the lens and of parameters concerning the morphologyof the wearer and the geometry of the selected frame. For one of the twomain faces of the lens, specifically the convex front face, a dockingand blocking axis, known as the boxing axis AB, is defined as being theaxis that is substantially normal to the surface of the correspondingface of said lens and passing through the boxing center CB.

The feeler, gripper, and third transfer means 7 are designed andarranged to cause a blocking chuck to dock against one of the two mainfaces of the lens (specifically the convex front face) by moving thefirst chuck in translation relative to the lens along the boxing axisassociated with said face. The blocking chuck is applied against theconvex front face by being brought up thereto in translation along thedocking direction AB, with this movement in translation being maintainedrigidly without any angular movement.

As can be seen more particularly in FIG. 15, the feeler, gripper, andthird transfer means 7 are in the form of a member or arm servingfirstly to feel the lenses L1 and L2 and secondly to handle the lensesfor transfer purposes (third transfer) towards the cutting-out device 6.

For this purpose, the feeler, gripper, and third transfer arm 7possesses a wrist 81 that has five controlled degrees of freedom ofmovement relative to the common frame comprising, in the configurationshown in FIG. 15: horizontal translation along the X axis, verticaltranslation along the Z axis, and three degrees in rotation about the X,Y, and Z axes.

In this embodiment, movement relative to these axes is controlled byelectric motor means. However, the person skilled in the art couldprovide for implementing other control means, such as pneumatic or othermeans. Regardless of the way in which drive is provided, it iscontrolled by the electronic and computer system 100.

In practice, and as shown in greater detail in FIG. 15, the wrist 81 ishinged to a support slab 80 so as to be capable of pivoting relativethereto about the X and Y axes. The slab 80 is itself mounted to move invertical translation along the Z axis on a vertical beam 82 that actsfor this purpose as a slideway. The vertical beam 82 is carried at itsbottom end by a turret 82.1 that is mounted to rotate about the Z axison a carriage 84. The carriage 84 is mounted on a horizontal beam 83associated with the common frame and forming a slideway for slidingalong the X axis. By way of example, the beam 83 may be secured to thestructure 31.

These five degrees of freedom of the wrist 81 in the stationary frame ofreference (X, Y, Z) are controlled by various electric motors driven viaa suitable power electronics card by the electronic and computer system100. Thus, rotations of the wrist 81 relative to the slab 80 about the Xand Y axes are controlled by respective motors 105 and 106. Verticalsliding of the slab 80 is controlled by a motor 107 associated with thebeam 82 and driving a screw 108 engaged in a nut 109 secured to the slab80. Rotation of the turret 82.1 carrying the vertical beam 82 about thevertical Z axis is controlled via a belt 111 by a motor 110 whose bodyis secured to the carriage 84. Finally, the horizontal sliding of thecarriage 84 is controlled by a motor 112 associated with the horizontalbeam 83 and driving a screw 113 engaged in a nut 114 secured to thecarriage 84.

In order to perform the distinct functions both of feeling and ofgripping, the wrist 81 of the arm 7 is provided with feeler means 85 andgripper means 86 that are distinct and independent of each other.

The feeler means 85 are arranged to feel, independently or incombination, the two main faces (front or convex face 8 and rear orconcave face 9) of the lenses L1 and L2. For this purpose, the feelermeans 85 have two branches 90 and 91 that are substantially rectilinearand that each of which terminates at a bent free end forming a feelertip 92, 93. The two tips 92, 93 of the two branches 90, 91 point towardseach other so as to be brought into contact with the front and rearfaces 8 and 9 respectively. Each of the two tips 92 and 93 has amechanical feeler of conventional type mounted thereon, operating merelyby mechanical contact.

One and/or the other of the two branches 90 and 91, and in this exampleboth branches 90 and 91 (see FIGS. 16 to 18) can be moved in translationon the wrist 81. This movement in translation enables the two tips 92and 93 to be moved apart or towards each other. The movement intranslation or the branches 90 and 91 are controlled independently ofeach other by electric encoder motors 180, 181 integrated in the housingof the wrist 81 and under the control of the electronic and computersystem 100. Movement in translation and continuous tracking of theposition of the branches 90 and 91 are performed by the electric motors180, 181 via respective rack-and-pinion mechanisms 184 & 182 and 185 &183, each pinion 182, 183 being driven by the corresponding motor 180,181, and the associated rack 184, 185 being secured to a correspondingbranch 90, 91.

The gripper means 86 are in the form of a blocking clamp constituted bya top jaw 95 and a bottom jaw 96 that are movable relative to each otherin translation or in pivoting. In the example shown, the bottom jaw 96is mounted to move on the wrist 81 so as to slide on a rail 87 in thesame direction in translation as the feeler branch 90, for example beingdriven in translation by a screw-and-nut mechanism 99 driven by anencoder motor integrated in the housing of the wrist 81. The top jaw 95is mounted stationary on the wrist 81.

The jaws 95 and 96 are substantially rectilinear in shape, beinggenerally parallel to the feeler branches 90, 91, and they are providedat their free ends with releasable clip-fastener means 97, 98implemented in this embodiment by an open C-shaped resilient ringconstituting a clip. These clip-fastener means are for receiving thechucks 101, 102 for gripping and blocking the lens.

The pair of chucks 101, 102 mounted in this way at the ends of thegripper jaws 95, 96 serve to grip the lens and subsequently, on thecutting-out means to block the lens which is sandwiched between them. Ingeneral, each chuck possesses both axial fastener means and alsotransverse fastener means. The two chucks are transferred by means ofthe feeler, gripper, and third transfer arm 7 together with the lensesthey are carrying or blocking, from the reception and first transfercarousel 2 to the cutting-out device 6. This is the third transfer ofthe lens in question, as is explained in greater detail below whendescribing the preparation method.

Nevertheless, attention is drawn at this point to an importantcharacteristic of the two functions performed by each chuck: thetransverse fastener means are arranged to co-operate with the arm 7 andthe axial fastener means are arranged to co-operate with the clampingand rotary drive shafts 612, 613 of the edger. The chucks 101, 102 thusperform two functions. When they are associated with the arm 7, theyconstitute endpieces of a clamp for gripping and transferring the lens.When they co-operate with the shafts 612, 613 of the edger, theyconstitute abutments for blocking and driving the lens in rotation. Itcan thus be understood that this third transfer of the lens performedwith the chuck engaging the lens presents the major advantage ofavoiding any loss of a frame of reference.

As shown in particular in FIGS. 28 to 31, each gripping and blockingchuck 101, 102 is generally in the form of a mushroom that is circularlysymmetrical about an axis which, in operation, is common to both chucks101, 102. More precisely, each chuck comprises respectively a centralpeg 161, 162 that is not deformable, extended outwardly by a collar 163,164 that is elastically deformable. Each collar is shaped to present abearing surface 165, 166 suitable for coming into contact with the lensL1 and for matching the shape thereof under the effect of an axialclamping force. Such an axial clamping force is applied in oppositedirections to both chucks together, either by the jaws 95, 98 of thethird transfer member 7, as shown in particular in FIG. 28, or by theshafts 613, 612 of the cutting-out means as they approach each other forfinal blocking of the lens on said shafts, as shown in FIGS. 29 and 30.In the example, the application surfaces 165, 166 have peripheralportions belonging to said collars, and central portions belonging tothe pegs themselves.

In addition, in the example shown, the application surface 165, 166 ofeach chuck is covered in a thin lining 167, 168 of plastics material orof elastomer material. The thickness of this lining is of the order of 1mm to 2 mm. By way of example, it may be constituted by flexible PVC orby neoprene.

As can be seen in FIG. 30, the application surfaces 165, 166 of the twochucks 101, 102 do not have exactly the same shape. The chuck 101 forco-operating with the front face of the ophthalmic lens has anapplication surface 165 that is concave in its unstressed state. Thechuck 102 that is for co-operating with the rear face of the ophthalmiclens has an application surface 166 that is substantially plane in itsnon-stressed state.

It is shown in greater detail that the chucks 101, 102 are transferredto the cutting-out means together with the lens they are gripping, andthus perform blocking of the lens against the cutting-out means withoutany other repositioning.

When difficulty is anticipated in cutting out the lens, because of thecoating material on the lens or because of the special shape to whichthe lens is to be cut, the blocking of the ophthalmic lens forcutting-out purposes can make use of a reference pad 145 either insteadof or in combination with the blocking chuck 101. Such a pad 145 isvisible in FIG. 32 and it possesses an adhesive application surface 147for being secured temporarily on the lens.

In contrast, the application surface 165 of the chuck 101 does notpresent any adhesive property, but is suitable for co-operating byfriction with the lens in order to prevent it from moving.

For co-operation between the reference lens 145 and the blocking chuck101, the central portion of the peg 161 of the chuck 101 is hollowed outand then presents a stepped axial housing 144 opening out to theapplication surface and arranged to receive the adhesive reference pad145, as is explained in greater detail below. The housing 144 opens outin the center of the application surface 165 of the blocking chuck 101.

The reference pad 145 is substantially smaller than the blocking chuck101, so as to be suitable for use with lenses of all shapes and sizes.Thus, the application surface 165 of the blocking chuck 101 possesses anarea that is at least four times greater than that of the applicationsurface 147 of the reference pad 145. Tests have served to optimize thedimensions of the application surfaces of the pad and of the chuck: theapplication surface 165 of the blocking chuck 101 preferably possessesan area lying in the range 80 square millimeters (mm²) to 500 mm², andthe application surface 147 of the reference pad possesses an area lyingin the range 20 mm² to 80 mm². The blocking chuck possesses an outsidediameter lying in the range 10 mm to 25 mm and an inside diameter lyingin the range 5 mm to 10 mm, and the reference pad 145 possesses adiameter that matches the inside diameter of the chuck, i.e. lying inthe range 5 mm to 10 mm.

In order to index the chuck 101 in rotation relative to the adhesivereference pad 145, the stepped housing 144 possesses a cross-section ofa shape that is not circularly symmetrical about the common axis AB. Inthe example shown, the section of the housing 144 is oval in shape.

The adhesive centering pad 145, that can be seen more clearly in FIG.32, possesses an outside shape that is stepped in complementary mannerto the housing 144 so as to be received in said housing withoutclearance, so as to be a snug fit. The common shape of the housing 144and of the pad 145 is not circularly symmetrical, as mentioned above, sothe pad 145 is in an indexed rotary position relative to the chuck 101.

The housing 144 is also arranged to receive the reference pad 145 insuch a manner that the application surface 147 of the reference pad 145is flush with the application surface 165 of the blocking chuck 101.Specifically, the adhesive reference pad 145 possesses an end shoulder146 that limits its axial stroke in the housing 144 and that carries anadhesive face 147 for sticking against the lens and that is flush forthis purpose with the application face 165 of the chuck 101 when theshoulder 146 is in axial abutment against the corresponding shoulder ofthe stepped housing 144.

As explained below when describing the method that is implemented, theadhesive reference pad 145 can thus be placed in the housing 144 of thechuck 101 so as to be optionally implanted with the chuck 101 and inaddition thereto on the lens for centering and blocking for cutting-outpurposes. When implanted on the lens in this way, the centering pad 145embodies the centering frame of reference determined by the measurementmeans 5 independently of any direct connection between the lens and thetransfer means 2 and 7 of the device.

By proceeding in this way, the centering frame of reference of the lensis embodied by the stuck-on pad 145 which remains permanently implantedon the lens even when the lens is unloaded from the device for mountingon a frame. It is thus possible to perform one or more repeat operationson the lens when it is particularly difficult to mount without losingthe centering frame of reference thereof, as usually happens withadhesive blocking accessories.

However, in accordance with the invention, this centering frame ofreference function is separated from the blocking function proper thatis used for transmitting torque to prevent the lens from turningrelative to the shafts 612, 613 of the edger. The torque transmissionfunction is always provided by the chucks 101, 102 of shape, dimensions,and material that are adapted to the lens being cut out. The adhesivecentering pad 145 can thus be unique, being suitable for all types oflenses and frames, being small in size firstly so as to avoid impedingcutting out of the lens when its outline needs to be brought to a verysmall size, and secondly to deposit adhesive over as small as possiblean area of the lens in order to reduce the risk of scratching duringcleaning. Only the chucks need to be adapted to the work that is to becarried out, as is explained in greater detail below.

The measurement means 5 are also designed to detect the presence or theabsence of the reference pad 145 in a predetermined location.

The carousel for the first and second transfers 2 is provided with means140 for receiving the reference pad 145. Specifically, and as can beseen more clearly in FIG. 32, the loading and unloading turntable 30 isfitted on its top face, beside each of the loading faces 36 and 38, witha vertical tenon 140 for receiving an adhesive centering pad 145. Slots142 are provided in the turntable about each tenon 140. These slots,specifically three for each tenon, are in the form of portions of a diskof diameter smaller than that of the centering pad that is to be engagedon the tenon 140 via a central bore (not shown in the figures) in thepad 145.

When the operator has loaded the adhesive centering pad 145simultaneously with loading a job on the turntable 30, the measurementdevice 5 detects that light 142 has been obstructed by said pad andinforms the electronic and computer processor system 100.

The manipulator arm 7 serves to implant the blocking chuck 101 and thereference pad 145 together on the lens. The electronic and computersystem 100 communicates with said measurement means 5 when they performtheir function of detecting presence, and it is thus informed about thepresence or the absence of a reference pad 145 on the turntable 30.

The electronic and computer system 100 is programmed to execute thefollowing conditional instructions:

-   -   if the presence of the reference pad 145 is detected, the        manipulator arm 7 is controlled to implant the reference pad 145        on the lens together with the blocking chuck 101;    -   else, the manipulator arm 7 is controlled by the system 100 to        implant the blocking chuck 101, alone.

The collar and the peg of each chuck 101, 102 are made as a single pieceout of the same material. Satisfactory results have been obtained byclamping the lens between the chucks using a clamping force lying in therange 400 newtons (N) to 1000 N, while making the peg and the collar outof a plastics material such as polyvinyl chloride (PVC).

For the thin lining enabling torque to be transmitted without slip, aplastics material or an elastomer should be selected that presents acoefficient of friction with the surface coating of the lens that is ashigh as possible.

Furthermore, and as can be seen in particular in FIG. 30, the peg 162 ofthe chuck 102 that is to come into contact with the concave rear face 9of the lens L1 is hinged by means of a cardan joint 115 to a fastenerportion 169. This fastener portion 169 is for connecting to the bottomjaw 96 of the member 7 or to the shaft 613 of the cutting-out means, thepeg 162 then possessing freedom of angular orientation about the ball115. This enables the peg 162 of the chuck 102 to match the localangular orientation of the rear face 9 of the lens in order to enablethe lens to be clamped against the other chuck 101 whose own peg 161 isrigidly secured to the top jaw 95 of the member 7 or to the shaft 612 ofthe cutting-out means, without causing the lens to tilt angularly orslide transversely. This enables the lens to be held and blocked stablyand accurately on the boxing axis AB. The ball joint 115 is of thecardan type, i.e. it is capable of transmitting torque about the axis ofthe chuck 102.

As mentioned above, the chucks 101, 102 perform two functions. Firstlythey serve to grip the lens starting from its loading position on theturntable 30 of the carousel during the first and second transfers 2when they present the lens in the intermediate position. Then, with thelens being held in this way by means of the chucks 101, 102, by thefeeler, gripper, and third transfer arm 7, this arm performs the thirdtransfer of the lens towards the cutting-out means 6. When the lens istaken over by the cutting-out means (passing the relay), the chucksretain a role of holding the lens by clamping and then perform a secondfunction, derived from the first, which consists in blocking the lens soas to enable it to be machined in co-operation with the rotary drive andclamping shafts of the cutting-out means 6. The chucks then constitutedrive abutments forming an integral portion of the cutting-out means 6.These various steps of the preparation method are described in greaterdetail below.

These two functions, firstly gripping and secondly blocking forcutting-out purposes, give rise to two mechanical interfaces beingpresent on the chucks 101, 102:

-   -   one interface is a transverse interface (i.e. operating        transversely relative to the axis of the chucks which coincides        with the chuck clamping axis AB) to co-operate with the        releasable clip-fastener means (clip means) 97, 98 of the        gripper jaws 95, 96 in order to secure the chucks 101, 102 in        temporary manner to said jaws;    -   the other interface is axial (i.e. operating along the axis of        the chucks which coincides with the axis of the shafts 612, 613        of the cutting-out means 6) to co-operate with the shafts 612,        613 of the cutting-out means in order to implement firm axial        clamping of the lens sandwiched between the chucks 101, 102 with        rotary torque being transmitted from the shafts to the lens        without slip.

Thus, in the example shown, for the releasable fastening of each chuck101, 102 to the corresponding jaw 95, 96, the clip rings 97, 98co-operate with receiver notches 171, 172 formed correspondingly in thechucks 101, 102 transversely to the axis of the chucks. Thus, when thechucks are fitted on the jaws 95, 96, their axes are parallel to thetranslation direction of the jaws, which corresponds to the clampingdirection. The two chucks thus face towards each other with theirapplication surfaces 165, 166 facing each other when they are clippedonto the ends of the gripper jaws 95, 96. The two chucks 101 and 102 canthen be moved towards each other or apart from each other in order togrip or release a lens.

For its mechanical interface with the shafts 612, 613 of the cutting-outmeans 6, each of the chucks 101, 102 co-operates with the free end ofthe corresponding shaft 612, 613 via a system for mutually engagingcomplementary male and female portions which, by co-operating shapes,deliver rotary drive without slack. More precisely, in the exampleshown, each chuck 101, 102 is provided with a housing 173, 174 that isnot circularly symmetrical about the axis of the chuck, but that, on thecontrary, presents a shape that is conical on an oval base. The housingis for receiving an endpiece 620, 621 of complementary shape withoutslack that is formed at the free end of the corresponding shaft 612, 613of the cutting-out means, so as to enable torque to be transmitted fromthe shafts 612, 613 to the chucks 101, 102, and thus to the clampedlens. In the example shown, the housing 173 of the chuck 101 is providedon the rear of the peg 161 remote from its application surface 165,while the housing 174 of the chuck 102 is formed in the rear of thefastener portion 169 remote from the ball 115. Each chuck is thusprovided with means for constraining it to rotate with the correspondingshafts 612, 613 of the cutting-out means. After being transferred to theshafts of the cutting-out means, the chucks thus constitute abutmentsfor driving the lenses in rotation.

As shown in FIG. 31, the mounting preparation device 1 of the presentinvention also includes a magazine of chucks 130 placed in the vicinityof the feeler, gripper, and transfer arm 7. This magazine houses threepairs of chucks in a stepped configuration so as to enable the chucks tobe taken easily by the arm 7.

By way of example, the magazine has three pairs 131 to 133 of chucksanalogous to the chucks 101, 102 and of sizes that are adapted to thedimensions of different jobs of lenses for cutting to shape, and ofmaterial adapted to the surface treatment of the lenses, and inparticular to the adhesive properties thereof. More precisely, thediameter of the application surfaces 165, 166 of the chucks is adaptedto the diameter of the frames in order to optimize torque transmissionand consequently machine speed.

A set of several pairs of chucks is arranged on the stepped magazine,and the appropriate pair of chucks is selected automatically. In theexample shown, the magazine 130 has three stages in a staircaseconfiguration. The top stage receives the pair of chucks 131 for cuttingout lenses around an outline of small diameter; the intermediate stagereceives the pair 132 for cutting out lenses around an outline of mediumdiameter; and the bottom stage receives the pair 133 for cutting outlenses around an outline of greater diameter.

The three stages of the magazine 130 are provided with cradles 134, 135,and 136 suitable for receiving the corresponding pairs of chucks 131,132, 133 with vertical relative movement. The two chucks of a pair thenrest in the cradle of the corresponding stage on a common axis, touchingeach other with their application surfaces one against the other.

The arm 7 is controlled by the electronic and computer system to pick upautomatically the best adapted pair of chucks as a function of theparameters of the lens job to be prepared. The appropriate pair ofchucks is taken by the arm 7 from the magazine 130 as follows. The jaws95, 96 are presented in a common horizontal plane that also contains thecommon axis of the chucks of the pair in question. The clip rings 97, 98fitted to the ends of the jaws 95, 96 then present their openings facingtowards the chucks of the pair in question. The wrist 81 of the arm 7 isthen advanced horizontally towards the chucks 101, 102 in such a mannerthat the clip rings 97, 98 engage in the notches 171, 172 about the pegs161 and the fastener portions 169 of the chucks 101, 102. With thechucks clipped in this way to the jaws 95, 96 of the arm 7, the wrist 81of the arm 7 is raised vertically so that the pair of chucks 131, 132,or 133 moves out form its receiver cradle 134, 135, or 136. When lenspreparation has been completed and the pair of chucks used for thatpreparation is not suitable for use in preparing the following lens, thepair of chucks is replaced in its associated receiver cradle 134, 135,or 136 in the magazine 130 by moving in the opposite direction,initially by being lowered vertically to engage the chucks in thecradle, and then withdrawing the wrist 81 of the arm 7 in a horizontalmovement against the resilience of the clip rings 97, 98 so as to forcethe rings to release the chucks.

In addition to the staged positioning of the various pairs of chucks inthe magazine, two mechanical keying systems serve to avoid any errorwhen distinguishing between the pairs of chucks.

A first mechanical keying system consists in the fact that the chuckcarrier cradle 134, 135, 136 provided at each stage of the magazine 130for each of the pairs of chucks possesses longitudinal and transversedimensions that match the pair of chucks it is to receive.

The second mechanical keying means comprise firstly transverse pluggingholes 120 formed in the peg 161 and in the fastener portion 169 of thechucks 101, 102, and secondly corresponding fingers or tenons (notvisible in the figures) fitted to the jaws 95, 96 and projectingtransversely into the clip rings 97, 98 in line with the jaws 95, 96 soas to co-operate with the transverse plugging holes 120 of the chucks101, 102. When the two chucks of a given pair are installed in themagazine, they are coaxially in abutment, and the holes 120 formed ineach of the chucks are spaced apart from the holes of the other chuck bya certain spacing that is specific to the pair of chucks in question,such that it is necessary for the electronic and computer system 100 toadjust the spacing between the branches of the gripper arm to match thespacing of the selected pair of chucks. If the spacing is wrong, thenthe keying fingers of the jaws 95, 96 of the arm will come into abutmentagainst the peg 161 and/or the fastener portion 169 of the chucks 101,102 and will not be able to penetrate into the transverse plugging holesof the chucks, thus preventing the rings 97, 98 from clipping onto thechucks in the notches 171, 172.

In a variant, provision could be made for the spacing of the pluggingholes 120 in the chucks stored in their cradles of the magazine to bethe same for all of the chucks, such that the jaws 95, 96 of the arm cantake hold of all of the chucks at a constant spacing regardless of whichpair of chucks is intended. Under such circumstances, keying consists,after the chucks have been taken by the jaws of the arms, in measuringthe spacing between the plugging holes 120 by clamping the two jawstogether so as to abut the chucks against each other and clamp thechucks against a reference spacer of known thickness. This measurementmakes it possible to verify whether the pair of chucks that has beentaken is the pair desired for cutting out the job being prepared.

Controlling Electronic and Computer System

The device 1 has a controlling electronic and computer system 100constituted in this example by an electronics card designed to controlin coordinated manner the measurement means, the cutting-out device, thereceiver and first and second transfer means, and the feeler, gripper,and third transfer means for automatically processing a lens inapplication of the automated processing method that is described below.

By way of example, and in conventional manner, the electronic andcomputer system 100 comprises a mother board, a microprocessor, randomaccess memory (RAM) and a permanent bulk memory. The bulk memorycontains a program for executing the automated method of preparinglenses for mounting in accordance with the invention and as describedbelow. This bulk memory is preferably rewritable and advantageouslyremovable in order to enable it to be replaced quickly or to beprogrammed on a remote computer via a standard interface.

Covering and Controlling Access

As shown more particularly in FIG. 2, the mounting preparation device 1of the present invention is enclosed in a cover 20 which preventsuntimely access to all of the component parts of the device.

The cover is in the form of a casing that presents a front face 21, andan opposite rear face 22. The front face 21 is designed to face theoperator and it possesses a top portion 23 and a bottom portion 24 thatare substantially vertical, these two portions 23 and 24 being spacedapart by a substantially horizontal flat 25.

An access door 26 is hinged to the flat 25 between a horizontal closedposition and a vertical open position as shown respectively in FIGS. 2and 3. Only this access door 26 hinged on the cover 20 gives access whenopen to the receiver and first transfer means 2, as described more fullybelow.

The device of the present invention thus makes it possible to automateall of the operations, avoiding any operator intervention, and thusminimizing risks.

Operation (Automated Processing Method)

The mounting preparation device described above is implemented using anautomated method that is described below.

In accordance with a specific characteristic of the invention, it isproposed to process lenses in jobs. The term “job” is commonly used inthe ophthalmic business and designates of a pair of associated lenses L1and L2 belonging to the same pair of eyeglasses and consequently formounting on the same frame to be worn by a user.

The device described also makes it possible to process a plurality ofjobs (typically two jobs) simultaneously, at least in part, i.e. one jobin the background while the other job is also being processed.

Automatic Processing for Preparing a Job for Mounting (First Job, J1)

Generically, the processing of a job comprises the following steps.

Preliminary step—Inputting or transmitting job input data.

As shown in FIG. 38, in order to achieve proper optical mounting, theframe selected by the user is placed on the user's nose in a preliminarystep and various measurements are performed thereon using an appliancereferred to as a “pupillometer” or “PD meter”, or any other appliancefor imaging or measuring morphology.

With the pupillometer, the operator obtains a certain amount of data,including:

-   -   the pupillary distance D representing the distance between the        two pupils P1, P2; and    -   the pupillary half-distances representing the distance between        each pupil P1, P2 and the center 13 of the nose of the frame        worn by the user.

Thereafter, the optician determines the height H that represents thedistance vertically below each pupil P1, P2 between the pupils P1, P2and the bottom edge of the rims C1, C2 of the frame worn by the user,with this being done manually for example, using a ruler, or by imaging.This height can be measured either using presentation eyeglassespossessing the frame selected by the user and having the locations ofthe user's pupils marked on its lenses with a felt tip so that thedistance can be measured with a rule, or else by means of a digitalsystem for taking an image and processing that image. This measurementthus includes information about the shape of the selected frame.

This information relating to the morphology of the user is then input bythe operator using an appropriate interface (typically a keyboard and ascreen) and is stored in a memory of the electronic and computer system100.

Furthermore, information representative of the outline of the selectedframe is also delivered to the electronic and computer system 100, whichputs that information in its memory. By way of example, the informationmay be selected by the optician and then extracted from a databasestored locally in the memory of the electronic and computer system 100,or from a remote server accessible over the Internet, or over a securepoint-to-point connection.

Finally, the optician or operator inputs into the memory of theelectronic and computer system 100 the parameters of the prescriptionrelating to the user for whom the job being prepared is intended. Thisincludes in particular the cylindrical power axes and the prismatic axesand powers, and possibly also cylindrical, spherical, and whereappropriate power addition powers.

Step 1.1—Presenting the loading and unloading turntable 30 in theloading position.

Where necessary, the electronic and computer system 100 controlsrotation of the loading and unloading turntable 30 to present two freeloading places 36, 37 in register with the access door 26.

Step 2.1—Opening the access door 26.

Initially, the access door 26 is held closed. As a general rule, theaccess door is kept closed so as to protect the internal members of themachine and in particular the loading and unloading turntable 30.

The access door of the device is opened at the request of the operator.At the request of the operator, opening of this door is authorized bythe electronic and computer system 100 in restrictive manner during theloading and unloading steps, as explained below.

Step 3.1—loading the lenses.

As can be seen in FIGS. 9 and 10, the loading and unloading turntable 30is turned so as to occupy identified positions, and in particular aloading position in which only two loading places 36 and 37 and twounloading places 41 and 42 are accessible to the operator after theaccess door 26 has been opened. The third loading place 38 and the othertwo unloading places 43 and 44 are masked by the remainder of the cover20. The operator thus cannot make a mistake when loading and unloadingjobs onto and off the turntable 30.

In this identified loading position, the clamps 46 and 47 correspondingto the loading places 36 and 37 are open and the two seats 34, 35 are inthe high position. In this high position, the seats 34, 35 mask theclamps 46, 47 laterally, thus acting in combination with the cover 20 toprevent firstly any untimely handling of the clamps by the operator, andsecondly any intrusion of an article into the inside of the device whichwould run the risk of damaging its moving internal components.

It is thus possible to load a first job of two lenses L1 and L2 on therespective bearing zones 72, 73 of the top faces 70 of the seats 34 and35. In practice, the two lenses L1 and L2 of the first job J1 are placedmanually by the operator on the two loading faces 36, 37 of the loadingand unloading turntable 30 that are accessible through the access door26. This is the only physical action taken by the operator on thelenses. Naturally, it is also possible to envisage loading the lensesautomatically.

Step 4.1—Lowering the seats and clamping the lenses.

The two seats 34 and 35 are then controlled so as to move towards theirlow position in which the lenses L1 and L2 are situated level with thefingers 56 of the respective clamps 46 and 47 (FIG. 11). The clamps arethen controlled to take up their closed positions so that the end platesof the fingers 56 are clamped against the lenses L1 and L2.

While the clamps 46 and 47 are closing, the crenellations 69 on eachclamp move into the groove 71 of the corresponding seat 34, 35 as theclamps close and turn, such that the clamps 46, 47 take hold of the edgefaces of the lenses over their entire thicknesses and extend beyond themon both sides.

The two lenses L1 and L2 of the first job J1 are thus clamped over thefull thickness of their edge faces by the clamps 46, 47 of the loadingand unloading turntable 30. It will be understood in particular thathaving the clamps projecting beyond the edge faces of the lenses on bothsides serve to ensure that the lenses are held securely and firmly, evenwhen they are of small thickness.

The third clamp 48 corresponding to the third loading place 38 remainsin the closed position (being urged thereto by the resilient means 57).

Step 5.1—Lowering the seats 34, 35 of the lenses.

With the lenses L1 and L2 gripped by the clamps, the seats of the lensesare retracted further downwards like an elevator so as to avoid anyrubbing during the following step.

Step 6.1—First transfer of the first lens: turning the loading andunloading turntable 30 so as to pass the first lens L1 of the job J1into the measurement device 5.

The entire turntable 30 together with its clamps 46 to 48 is turnedsimultaneously so as to bring the first lens L1 of the first job intoregister with the measurement device 5 (FIG. 12). This turning of theturntable 30, when seen from above, takes place in the clockwisedirection under the control of the electronic and computer system 100.

In the above-mentioned variant, during this turning movement, the clampsare guided by the crenellations 69 of the fingers 56 which co-operatewith the beads 75, 76.

Step 7.1—The measurement device 5 reads the first lens L1 of the job J1.

The shape and the optics of the lens L1 are analyzed by the measurementdevice 5 automatically in the manner described above so as to providethe electronic and computer system 100 with data relating mainly to theoptical powers and to the frame of reference of the lens (centeringpoint and orientation). These optical power and referencecharacteristics are stored by the electronic and computer system 100.

In particular, the acquisition of the reference characteristicsmentioned above makes it possible in association with the geometricaland morphological data acquired during the above-described preliminarystep to determine the exact point whereby the ophthalmic lens L1 isgripped and blocked on the carousel of the receiver and first and secondtransfer means 2 moved into the intermediate position (as explainedbelow), and to determine the cutting-out parameters so as to control thecutting-out device 6 accordingly while it is cutting the lens to shape.

The measurement device 5 thus also determines one or more local opticalcharacteristics at one or more remarkable points of the lens that are ofinterest for characterizing or verifying the lens or the job. This orthese characteristics are stored in a memory of the electronic andcomputer system 100. They are subsequently reprocessed (see inparticular Step 9.1) by the electronic and computer system so as to becombined with or corrected as a function of geometrical data provided bythe arm 7 performing its feeler function and relating to the position inthree dimensions of the lens being prepared on the turntable 30 in aframe of reference associated with the measurement device 5.

Step 8.1—Second transfer of the first lens: turning the loading andunloading turntable 30 to enable the first lens L1 of the job J1 to befelt.

The turntable 30 is turned clockwise to bring the lens L1 into aso-called “intermediate” position in which said lens is close to the arm7 so as to be accessible to said arm firstly to be felt thereby andsecondly to be taken thereby, as explained in the following steps.During this second transfer, the turntable 30 is turned and monitored bythe electronics for controlling rotation of the turntable 30 and themovement is stored in a memory of the electronic and computer system100. Simultaneously, the position and the axis of the lens measured bythe measurement device 5 during the preceding step are tracked andretained in memory.

Step 9.1—Feeling the first lens L1 of the job J1 at its optical centeror reference center, and/or at any point of interest or any remarkablepoint (measurement point) of the lens.

FIG. 19 shows the feeler, gripper, and transfer arm 7 while it isfeeling the lens L1 in order to determine the height or altitude e ofthe lens L1 relative to the device 5 for measuring the level of one ormore remarkable points on the lens in preparation by feeling, the pointsbeing those at which it is desired to make a measurement of one or moreoptical characteristics such as optical powers (i.e. vertex ophthalmicpowers). One such remarkable point, for example, is the reference centerCR (optical center for a single-vision lens and mounting cross for aprogressive lens) on the concave face of the lens. More generally, thispoint which may be any point of interest where it is desired to measurea local, spherical, or cylindrical vertex optical power. Typically, itmay be the optical center of a single-vision lens or the referencepoints for near and far vision for a progressive lens.

It is known that the spherical or cylindrical ophthalmic power isdefined as the reciprocal of the distance between the focus(es) and theconcave rear face of the lens. The measurement device 5 enables theposition(s) of the focus(es) to be measured in the fixed frame ofreference of the device. Feeling the concave face of the lens at thepoint of interest makes it possible to measure its position in the frameof reference, and thus the distance(s) between the measured focus(es)and the rear face of the lens.

More precisely, the procedure is as follows.

The measurement means 5 initially determine a local opticalcharacteristic at one or more remarkable points of the lens that are ofinterest for characterizing or verifying the lens or the job. Thecharacteristic is stored in a memory of the electronic and computersystem 100.

The arm 7 performing its feeler function is controlled by the electronicand computer system 100 in order to determine the position, i.e.specifically merely the altitude, of the or each remarkable point on oneof the faces of the lens.

This position is stored in the memory of the electronic and computerprocessor system 100 so as to be combined with the value previouslystored in Step 7.1 for the local optical characteristic at the point inquestion. This combination is performed by software comprisingcalculation instructions which, by combining the position of theremarkable point as obtained by feeling with the local characteristic ofthe lens as determined by the optical measurement device 5, deducestherefrom the spherical and/or cylindrical powers of the lens at theremarkable point, e.g. the spherical powers at the reference points fornear vision and for far vision. The spherical or cylindrical ophthalmicpower is then calculated as being the reciprocal of the distance betweenthe focus(es) and the concave rear face of the lens.

In practice, two modes of operation can be envisaged.

In a first mode, the measurement device 5 determines the position of afocus of the lens at said remarkable point or point of interest. Thecalculation instructions of the program executed by the system 100 thendeduce the focal length of the lens at the remarkable point in questionby associating (or combining) the position of the remarkable pointobtained by feeling with the position of the focus of the lensdetermined by the optical measurement performed by the measurementdevice 5. The program then calculates the vertex optical power as beingthe reciprocal of said focal length found in this way.

In a second mode, the measurement device 5 determines an approximatevalue for the power of the lens at a remarkable point of the lens. Thecalculation instructions of the program executed by the system 100 thencorrects the approximate value for the power of the lens obtained byoptical measurement as a function of the position of the remarkablepoint as obtained by feeling. This correction is carried out by theprogram by means of a mathematical correction formula resulting bothfrom the approximation made during the optical measurement forevaluating the power at the point in question, and from the fact thatthe optical power is equal to the reciprocal of the focal length.

During this first feeling operation, only the concave (bottom) face 9 ofthe lens is felt by the tip 93 of the bottom branch 91. In a variant, itis naturally possible to feel the convex top face 8 of the lens L1 bymeans of the other tip 92 carried by the top branch 90 of the feelermeans 85.

Step 10.1—Feeling the outline of the first lens L1 of the job J1.

The feeler, gripper, and third transfer arm 7 then feels the outlineintended for the lens after it has been cut to shape in order to verifythat the lens presents sufficient surface and thickness to enable thedesired lens to be obtained after being cut to shape in the cutting-outdevice 6. For example, the outline T is represented in FIG. 20, whileFIGS. 16 to 18 show the approach movements of the tips 92, 93 of thefeeler means 85.

The wrist 81 is initially moved to bring the two tips into the vicinityof the periphery of the lens. In the example shown, the bottom tip 93(FIG. 17) is the first to be put into contact with the rear face 9 ofthe lens L1 by moving the branch 91 that carries this tip intranslation. Then the top tip 92 is moved by moving the branch 90 intranslation to feel the front face 8 of the lens (FIG. 18). The assemblyis then moved by the wrist 81 so that the tips 92, 93 feel the outlineof the lens. Nevertheless, this example is not limiting and an oppositesolution could be envisaged with the top tip being the first to makecontact, or indeed a combined solution with both tips being approachedand put into contact simultaneously.

Step 11.1—Feeling a plurality of points in the vicinity of the boxingcenter of the first lens L1 of the job J1 and points for determining thenormal at the boxing axis.

The boxing axis, as defined above for implementing the invention, isthen determined by feeling (FIG. 21), using the tips 92, 93 broughtsuccessively into contact with the lens as in the preceding step, at aplurality of points (at least three points) situated in the vicinity ofthe boxing center CB, and specifically at four points A, B, C, and D.

Step 12.1—First transfer of the second lens: turning the loading andunloading turntable 30 to bring the second lens L2 of the job J1 intothe measurement device 5.

Step 13.1—Reading the second lens L2 of the job J1 in the measurementdevice 5.

Step 14.1—Second transfer of the second lens: turning the loading andunloading turntable 30 to go into the intermediate position in order tofeel the second lens L2 of the job J1.

Step 15.1—Feeling the second lens L2 of the job J1 at its opticalcenter.

Step 16.1—Feeling the outline of the second lens L2 of the job J1.

Step 17.1—Feeling a plurality of points in the vicinity of the boxingcenter of the second lens L2 of the job J1 and feeling points fordetermining the normal at the boxing axis.

Step 18.1—Comparing the characteristics of the first job J1 with theinput data.

The internal program of the electronic and computer system 100 carriesout a confirmation examination, automatically or with assistance, on thecharacteristics of the two lenses L1 and L2 of the job J1. Thisconfirmation examination consists in making two verifications:

-   -   firstly individual verification that the characteristics of each        lens of the job comply with the prescription input by the        operator into the memory of the electronic and computer system;        and    -   secondly, checking that the overall characteristics of both        lenses considered as a single job, i.e. as a function of        belonging to the same pair of eyeglasses, make sense, in        particular by simulating mounting the two lenses on the selected        frame and verifying that such mounting is possible.

The characteristics for which each lens is validated individually are inparticular:

-   -   type of lens: single-vision, progressive, bi- or trifocal, etc.;    -   spherical, prismatic, cylindrical powers;    -   power addition(s) for progressive lenses;    -   cylinder and prism axes;    -   hue;    -   index;    -   material.

The characteristics for which the two lenses of the pair are consideredtogether as belonging to the same job are in particular:

-   -   the centering of each lens on the frame as a function of the        frame of reference defined by means of the measurement device 5        for each lens, and the pupillary half-distances and heights        specific to the user, this centering making it possible to        simulate mounting of the lenses on the frame for which they are        intended, as explained in greater detail below;    -   the intended axial position for the bevel or groove on the edge        face of each lens relative to the front face of the lens, in        order to ensure that the mounted frame is pleasing in appearance        (balanced axial positioning for the two lenses relative to each        other on the frame);    -   matching of the hues, indices, shades of the two lenses of the        job; and    -   complementarity of the two lenses, checking they both belong to        the same job: it is verified that the job is indeed made up of a        right lens and a left lens and that these two lenses do indeed        correspond to a single job.

In particular, the overall reconciliation of the identificationcharacteristics of the job is performed as follows. Starting frominformation representative of the parameters specific to the morphologyof the user, in particular the pupillary half-spacing and the pupillaryheight relative to the horizontal axis, and starting from informationrepresentative of the outline of the selected frame, acquired during theabove-described preliminary step, the electronic and computer system 100generates a video image that is displayed on the display screen such asan LCD screen (not shown). Consequently, there can be seen on thescreen, specifically the outline of the frame and the outline of thelens prior to being cut to shape, both being shown at the same scale,together with the special characteristics of the lens, in particular theidentification points that are marked thereon or those that have beendetermined by using the measurement device. Taking account of all ofthese items, whether measured, calculated, or read, makes it possible todetermine the position of the perimeter of the lens as cut to shapecompared with the initial ophthalmic glass, and as a result the positionof the point where the lens should be gripped for cutting-out purposes,which is generally the center of the rectangle in which the outline of arim of the frame is inscribed.

The electronic and computer system 100 performs computer processing onthis geometrical and morphological data in association with the datarelating to the identification characteristics of the ophthalmic lensesL1 and L2 of the job J1 taken together in order to simulate mountingthem in the corresponding rims Cl and C2 of the selected frame M, andpossibly modifying their centering. FIGS. 39 and 40 are diagrams showingdifferent steps in this combined centering of a pair of ophthalmiclenses constituting a single job in the rims of a frame selected by theuser.

As shown in FIG. 39, each ophthalmic lens L1, L2 is positioned in eachof the rims C1, C2 so as to make the optical center or reference centerCR thereof (mounting cross 11, FIG. 35, if the lens L1 is a progressivelens) coincide with the determined position of the pupil P1, P2 of theuser relative to the rim C1, C2 of the frame M. When the initialdiameter of the ophthalmic lenses L1, L2 is too small relative to therims C1, C2 of the selected frame M, then a gap is created between therim C1, C2 of the frame M and the edge B1, B2 of the lens L1, L2.

Initially, both ophthalmic lenses L1, L2 are displaced (virtually)together (in this case along arrow F) while keeping constant therelative centering height H of the two ophthalmic lenses (the relativeheight being defined as the difference between the centering heights Hof the two ophthalmic lenses) and also keeping constant the pupillarydistance D between the two optical centers or reference centers CR ofthe ophthalmic lenses L1, L2 as positioned during the above step so asto eliminate the points of intersection found between each of the rimsC1, C2 of the frame M and the edges B1, B2 of the ophthalmic lenses.

Nevertheless, if after such (virtual) displacement of both ophthalmiclenses L1, L2 there still remain points of intersection between at leastone of the rims C1, C2 of the frame M and the edge B1, B2 of thecorresponding ophthalmic lens L1, L2, then in a second stage, one of thetwo lenses or both of the ophthalmic lenses L1, L2 is/are moved whileconserving the relative centering height H of the ophthalmic lenses andslightly modifying the pupillary distance between the two opticalcenters or reference centers of the ophthalmic lenses as positioned inthe preceding step in order to eliminate all points of intersectionbetween each rim of the frame and the edge of the correspondingophthalmic lens.

Under all circumstances, it is preferable, although not essential duringcombined (virtual) displacement of said ophthalmic lenses L1, L2, toconserve the relative centering height H of said lenses so that once theophthalmic lenses L1, L2 have been mounted in the rims C1, C2 of theselected frame, both optical or reference centers CR of the ophthalmiclenses L1, L2 and the pupils P1, P2 of the user are situated on the samehorizontal or level line (see FIG. 40) even if they do not coincide.

As shown in FIG. 40, since the height H and the pupillary distance D areconserved, the user need only look a little to the left or the right inorder to obtain correct vision at infinity.

At worst, if the pupillary distance between the ophthalmic lenses formounting is not complied with, the user will be obliged to converge ordiverge the eyes slightly when looking at infinity.

The electronic and computer system 100 displays the values of the prismsinduced for each eye by any modification to the centering of each lensin the frame. It is then up to the optician to determine whether thesevalues are acceptable or not, and, on that basis, accept or refuse thejob as recentered in this way. The system may optionally itself refuse ajob or warn the optician via a graphical and/or audible interface in theevent of at least one of these values exceeding a maximum thresholdvalue. Provision can also be made for the electronic and computer system100 to accept a job automatically if the induced prism values are lessthan a predetermined threshold value.

The electronic and computer system 100 also verifies that each nearvision zone 14 (FIG. 36) is properly situated within the cutoutperimeter of the lens and it enables the optician to verify thisvisually by displaying the corresponding zone.

Finally, the electronic and computer system 100 compares by calculationand/or displays for comparison by the optician's judgment, the axialposition intended for the bevel or the groove on the edge face of eachof the two lenses. This serves to assess the expected axial position ofeach of the two lenses when mounted in the frame, or in other words thepositions of the rims or rimless strings of the frame relative to thefront faces of the lenses. This calculation or visual comparison seeksto ensure that the positions of the rims or rimless strings of the frameare homogenous relative to the front faces of the lenses so as to avoidexcessive asymmetry in the axial positioning of the left and rightlenses relative to each other. Where appropriate, the axial position ofa bevel or a groove in one or other of the two lenses may be modified.

Alternatively, it can also happen that mounting the lenses L1, L2, or atleast one of them, is not possible or desirable because of somemechanical impossibility or because of the visual discomfort that suchmounting would inflict on the user.

Step 19.1—Accepting or refusing the first job J1

The job J1 is accepted or refused depending on whether theabove-mentioned individual and overall characteristics are or are notvalidated and/or modified.

Alternative 1: If the first job J1 is refused (alternative 1), then thefive following steps are performed. Otherwise they are ignored.

Step 20.1—Turning the loading and unloading turntable 30 to bring thefirst job J1 into register with the access door 26 (fifth transfer).

Step 21.1—Opening the clamps of the loading and unloading turntable 30and raising the seats of the lenses to the high position.

Step 22.1—Opening the access door under the control of the operator.

Step 23.1—The operator removing the first job J1.

Step 24.1—Loading the following job for processing, in the mannerdescribed at Step 3 et seq.

Alternative 2: If the first job J1 is accepted (alternative 2 being themore probable), the five preceding steps are ignored and the followingsteps are performed.

Step 25.1—The loading and unloading turntable 30 is turned so as topresent the first lens L1 of the job J1 in the intermediate position sothat it can be taken by the feeler, gripper, and third transfer arm 7(end of second transfer).

Step 26.1—Selecting and clipping machining chucks by the feeler,gripper, and third transfer arm 7 in the chuck magazine 130.

In practice, the two preceding steps are performed simultaneously withStep 18.1 and/or 19.1 in which the characteristics are compared and thejob is accepted or refused. Steps are thus performed in parallel inorder to save time, given that the first job J1 will usually beaccepted.

Step 27.1—The first lens L1 of the job J1 is taken by the feeler,gripper, and third transfer arm 7.

After performing the above-described feeling operations, the feeler,gripper, and third transfer arm 7 sandwiches the lens L1 between the twochucks 101 and 102.

A blocking axis AB (FIG. 14) is defined above referred to as the boxingaxis, being the axis that is normal to the front face of the lens andthat passes through the boxing center CB. In order to avoid positioningerrors, the top chuck 101 engages the convex front face of the lens bymoving in translation along said boxing axis AB of the lens and itremains pressed against the lens, being held on said axis. The surfaceof the chuck 101 is moved towards the front face of the lens 8 whilealready parallel to the plane that is tangential to said lens at theboxing center CB (FIG. 14). Docking occurs when the set of pointsconstituting the application surface 165 of the chuck 101 makes overalland simultaneous contact with the facing face of the lens, without anytilting. This avoids any offset or angular tilt error occurring duringdocking of the chuck against the lens. Because of this precision, it ispossible to rework the lens subsequently because any risk of positioningerror is eliminated.

These docking movements and this blocking configuration are madepossible by the numerous degrees of freedom of the wrist 81. As shown inFIGS. 22 to 24, the movement of the wrist 81 is adapted to begin bymoving up the top chuck 101. The top jaw 95 is stationary relative tothe wrist, and the chuck 101 is moved up to the lens by moving the wrist81 in translation and in rotation.

Thereafter, the screw 99 causes the bottom jaw 96 to move in translation(FIG. 24) so as to move the second chuck 102 up to the lens in the samemanner along the boxing axis AB. As can be seen more clearly in FIG. 30,the ball mount of the chuck 102 makes it possible for this chuck, whileit is docking against the rear face 9 of the lens, to take up the localangular orientation of said rear face 9 of the lens so as to enable thelens to be blocked against the other chuck 101 which is rigidlyconnected to the top jaw 95, without modifying in uncontrolled mannerthe position of the lens as would happen by causing it to tilt angularlyor to slide transversely.

The two chucks are then accurately engaged against the lens which isheld firmly. This procures blocking to the lens that is stable andaccurate on the boxing axis, without any geometrical error.

In this stage of the lens being held by the gripper means, it should beobserved that the frame of reference of the lens, defining its centeringand its orientation (the direction of its axis) and that has beenmeasured by the measurement device 5, is conserved or tracked by theelectronic and computer system 100 during the second transfer of thelens by the turntable 30 between the measurement position and theintermediate position. The chucks, presenting fastening configurationson the jaws 95 and 96 of the arm that are accurately known byconstruction, are thus engaged against the lens so as to take hold of itin a configuration (positioning in the plane of the lens andorientation) that is known relative to the frame of reference of thelens. The chucks 101, 102 are thus implanted against the lens with anorientation and a position in the plane of the lens that can bearbitrary but that is always accurately known and stored in a memory ofthe electronic and computer system 100.

Specifically, when clamping the chucks 101, 102 against the lens, noprovision is made for adjusting the angular orientations of the chucksrelative to the lens about the common blocking axis AB. Theseorientations, which can be arbitrary, are stored and embodied by thechucks themselves (ignoring a constant, but known angular offset). Thisknown angular offset is taken into account while cutting out the lens.

Nevertheless, in certain particularly difficult circumstances or inorder to further improve the accuracy and security with which the chucksare placed, in particular when reworking a lens in order to make acorrection, it is also possible to stick an adhesive centering pad 145on the lens while simultaneously clamping the chucks against the lens.

When the operator has loaded an adhesive centering pad 145simultaneously with loading a job on the turntable 30, the measurementdevice 5 detects the light 142 being obstructed by said pad and informsthe electronic and computer system 100.

In the absence of a pad on the tenon 140, the manipulator arm 7 iscontrolled by the system 100 to engage the blocking chuck 101 on itsown.

If the presence of the reference pad 145 is detected, then themanipulator arm 7 is controlled to engage the reference pad 145 on thelens together with the blocking chuck 101. The feeler, gripper, andthird transfer member 7 is then controlled by the system 100 in order totake hold of the pad so as to engage it against the front face 8 of thelens. More precisely, the feeler, gripper, and third transfer member 7brings the chuck 101 up to the pad on the turntable and lowers the chuck101 so that it becomes engaged with a small amount of grip on the pad,via the central housing 144 formed in the peg 161 of the chuck 101. Thepad is thus a tight or snug fit in the chuck 101 and it is conveyedtherewith towards the lens that is to be held and blocked. While thechucks 101, 102 are being clamped onto the lens by the branches 95, 96of the member 7, the adhesive face 147 of the pad comes into contactwith the convex front face of the lens, and it adheres thereto. The pad145 then remains engaged on the prepared ophthalmic lens until it isvoluntarily removed therefrom by the operator, and while it is engagedthereon it embodies the centering or identification frame of referenceof the lens as measured by the measurement device 5, thus enabling thelens to be reworked on one or more occasions.

By proceeding in this way, the centering frame of reference of the lensis embodied by the stuck-on pad 145, as is usually the case. However, inaccordance with the invention, this centering function is dissociatedfrom the blocking function proper that serves to transmit torque bypreventing the lens from turning relative to the shafts 612, 613 of theedger. This torque transmission function is always provided by thechucks 101, 102 which are of shape, dimensions, and material that areadapted to the lens that is to be cut out.

Step 28.1—Opening the clamp holding the first lens L1 of the job J1 onthe turntable.

Step 29.1—Third transfer of the first lens L1 of the job J1 for the gorelay handover from the carousel to the cutting-out means.

The lens L1 is then moved by the feeler, gripper, and third transfer arm7 (FIG. 5) so as to be taken off the loading and unloading turntable 30.Thereafter, the lens is transferred by said member 7 to the cutting-outdevice 6, as shown in FIGS. 26 and 27.

FIG. 28 shows the final stage of the transfer during which the lens L1is held simultaneously by the feeler, gripper, and third transfer arm 7,and by the shafts 613, 612 of the cutting-out means 6. In this state,the chucks 101, 102 are held by transverse clip-fastening by the top andbottom jaws 95 and 96 of the wrist 81, and by axial blocking by means ofthe shafts 613, 612 along the boxing axis, the shafts 613, 612 keepingthe lens that is to be cut out clamped in a sandwich between the twochucks 101, 102 via its center.

The wrist is then controlled to move so as to withdraw transversely anddisengage the jaws 95 and 96 away from the chucks 101, 102 so that thelens remains held merely between the chucks, on the cutting-out device(FIG. 29). During this transfer, there is no loss of frame of referencesince the chucks remain permanently in identified positions that belong,so to speak, both to the gripper arm and to the clamping and driveshafts of the cutting-out device. Given that the frame of reference ofthe lens has already been stored in memory, the electronic and computersystem 100 deduces therefrom the position and the orientation of theframe of reference of the lens in the frame of reference of thecutting-out device.

FIG. 30 is a longitudinal section of the two shafts 613, 612 inengagement with the two chucks 101, 102 by mutual interfitting.

Step 30.1—Feeling the first lens L1 of the job J1 in the cutting-outdevice 6.

Prior to machining and in order to ensure that machining is accurate,the first lens L1 of the job J1 is felt while it is installed in thecutting-out device 6 by being blocked and rotated between the shafts ofthe edger, feeling being performed by the feeler, gripper, and thirdtransfer arm 7. This feeling is carried out along the desired outlinethat it is assumed the lens will have after being cut out (takingaccount of the lens being transferred without losing its frame ofreference) and as a function of the identification characteristics ofthe lens provided by the measurement device 5 and the morphological dataof the user and the shape of the frame as input into the memory.

This feeling makes it possible to acquire in the memory of theelectronic and computer system 100, concretely and with great precision,the three-dimensional configuration of the lens blocked between theshafts of the edger, with account being taken of any deformation towhich the lens might be subjected due to the lens being clamped betweenthe chucks under thrust from the shafts. The electronic and computersystem 100 then deduces therefrom by calculation the precise parametersfor machining: the outline of the lens, the three-dimensional shape ofthe bevel or the groove, and the position and orientation of the drillholes.

Step 31.1—Machining (cutting out) the first lens L1 of the job J1 in thecutting-out device 6.

The electronic and computer system 100 controls the cutting-out device 6to machine the periphery of the lens so as to cut it out to the desiredoutline, given the identification characteristics of the lens assupplied by the measurement device 5 and the data concerning themorphology of the user and the shape of the frame as input into thememory.

Depending on the type of frame for which the job J1 being processed isintended (frame with rims, frame without rims and having drilled lenses,frame with rims constituted by Nylon string), the lens is beveled,drilled, or grooved.

Step 32.1—Positing the loading and unloading turntable 30 for removal ofthe first lens L1 of the job J1 by the feeler, gripper, and firsttransfer arm 7.

The loader and unloader turntable 30 is turned so as to bring theunloading place into register with the cutting-out means 6, in apredetermined position where the arm 7 will place the cutout lens.

Step 33.1—Fourth transfer of the first lens L1 of the job J1 to pass thelens back from the cutting-out means to the carousel.

After being cut out by the cutting-out device 6, the lens is taken holdof again by the feeler, gripper, and third transfer arm 7 so as to beplaced on an unloading place in one of the pairs of unloading places 41to 44 (FIG. 33).

The lens L1 is taken by the feeler, gripper, and third transfer arm 7while still in the cutting-out device 6 so as to enable it to be put onan unloading place of the loading and unloading turntable 30. This stepis performed simultaneously with the preceding step so as to beperformed in parallel, thus saving overall processing time. Naturally,the turning of the loading and unloading turntable to bring it intoposition is terminated before the lens is put into place by the arm 7.

This shows the advantage of the particular arrangement of the loadingand unloading turntable with its three loading faces and its fourunloading faces.

Step 34.1—Placing the first lens L1 of the job J1 in the unloading placeon the turntable of the carousel.

In order to place the cutout lens L1 on one of the unloading recesses 42to 44, the arm 7 presents the lens horizontally and outside theturntable 30, slightly above it, so that the bottom chuck engaged withthe lens is situated radially in register with the outside end of thetongue 49 associated with the radial slot 45 of the unloading recessconcerned. The wrist 81 of the arm is then moved in a radial directionof the turntable 30 so that the bottom chuck penetrates into theturntable 30 via the radial slot 45, pushing the tongue 49 into theretracted position against its return spring.

When the axis of the chuck reaches the center of the unloading recessconcerned, the arm moves downwards in order to place the lens on theturntable. Thereafter, the bottom jaw 96 of the arm 7 is loosened so torelease the lens, and the wrist 81 of the arm 7 withdraws radiallyoutwards so as to disengage the turntable 30, allowing the tongue 49 toreturn to its outer position overlapping the slot 45.

Step 35.1—Turning the loading and unloading turntable 30 to present thesecond lens L2 of the job J1 in the zone for being taken by the feeler,gripper, and third transfer arm 7 (end of second transfer).

Step 36.1—Taking the second lens L2 of the job 1 by the feeler, gripper,and third transfer arm 7 along the boxing axis.

Step 37.1—Third transfer of the second lens L2 of the job J1 for the gotransfer of the lens L2 from the carousel to the cutting-out means.

Step 38.1—Feeling the second lens L2 of the job J1 in the cutting-outdevice 6.

Step 39.1—Machining the second lens L2 of the job J1.

Step 40.1—Fourth transfer of the second lens L2 of the job J1 to returnthe lens L2 form the cutting-out machine back to the carousel.

Step 41.1—Placing the second lens L2 of the job J1 on the unloadingplace of the loading and unloading turntable 30.

Step 42.1—Fifth transfer: turning the loading and unloading turntable 30to present the first job J1 for unloading by the operator.

Step 43.1—Opening the access door 26 to unload the first job J1.

The access door 26 is opened to allow the operator access to theprepared job J1 at the request of the operator and under the control ofthe electronic and computer system 100 that allows the door to be openedonly when the turntable 30 is in the loading and unloading position.

Step 44.1—Unloading the first job J1 by the operator.

It is then possible to proceed with loading and processing another job(third job J3). The cycle then restarts at step 4.

Processing a Second Job (Job J2) Parallel with a First Job (Job J1)Itself Being Processed)

In accordance with an advantageous aspect of the method, partiallysimultaneous processing is proposed of two jobs (pairs of lenses eachassociated with a respective pair of eyeglasses).

FIG. 35 shows that the device 1 advantageously enables two jobs to beprocessed simultaneously. A second job can be loaded on the loadingplaces 37, 36 while the first lens of the first job is in thecutting-out device 6 and the second lens of that first job is beingprocessed by the measurement device 5.

Under such circumstances, the processing of the first job J1 takes placeas described above, and the steps of the following job J2 are analogous.The processing of the second job J2 then comprises steps referenced 1.2to 44.2 which are analogous respectively to the steps 1.1 to 44.1 forprocessing the first job J1.

Nevertheless, the invention makes provision for processing the two jobsin parallel, at least in part. In other words, certain steps of theprocessing of job J2 take place simultaneously with other steps in theprocessing of the job J1.

The processing of the second job can begin as soon as the go relayhandover has been accomplished for the first lens L1 for the first jobJ1 from the loading and unloading turntable to the cutting-out means 6,as provided for in step 29.1. A corresponding loading place on theloading and unloading turntable 30 is then left empty by the first lensL1 of the first job J1.

The processing of the second job J2 then takes place in parallel withthe steps 30.1 et seq. of the processing for the first job J1.

More precisely, the steps going from step 1.2 of presenting the loadingand unloading turntable 30 in the loading position to step 19.2 ofaccepting or refusing the job J2 are performed in parallel with the step31.1 of machining the lens L1 of the job J1.

The following steps going from step 25.2 of selecting the machiningchucks to the end of processing job J2 are performed after step 41.1 ofplacing the second lens L2 of the job J1 on the unloading plate of theloading and unloading turntable 30.

1. A method of preparing ophthalmic lenses for mounting performed usinga device comprising optical measurement means (5), geometricalmeasurement means (7); and an electronic and computer system (100), themethod comprising the following steps: an optical measurement step foracquiring centering characteristics of the lenses; and a geometricalmeasurement step for acquiring geometrical data of the lenses; whereinthe lenses are processed together in pairs of two lenses belonging to asame job, said processing comprising: during the optical measurementstep and the geometrical measurement step, optically measuring at leastone of the two lenses of the job, and geometrically measuring at leastone of the two lenses of the job; reconciling the detected centeringcharacteristics and the geometrical data obtained for both of the lensesof the job considered together, by comparing the centeringcharacteristics and the geometrical data of one of the two lenses withthe centering characteristics and geometrical data of the other of thetwo lenses; and confirming or refusing said job as a function of theresult of said reconciling step and information relating to themorphology of the user and a selected optical frame.
 2. The methodaccording to claim 1, in which, if the job is confirmed, both lenses ofthe job are cut to shape, or if the job is refused, preparation of bothlenses of the job is stopped.
 3. The method according to claim 1,including storing in memory said information relating both to themorphology of the user and to the shape of the selected frame.
 4. Themethod according to claim 3, including, in the event of some difficultyin mounting being foreseen during the comparison, modifying together thecentering characteristics of both lenses of a given job.
 5. The methodaccording to claim 1, in which the geometrical measurement of the saidlens comprises a first measuring step prior to said lens being blocked,during which said lens is measured around an outline desired for itsmounting.
 6. the method according to claim 1, in which the geometricalmeasurement of said lens comprises a second measuring step after saidlens has been blocked on a cutting-out means, during which said lens ismeasured around an outline desired for its mounting.
 7. A device forpreparing ophthalmic lenses (L1, L2) for mounting, the devicecomprising: optical measurement means (5) for acquiring centeringcharacteristics of the lenses; geometrical measurement means (7) foracquiring geometrical data of the lenses; an electronic and computersystem (100) for processing lenses by pairs of associated lensesbelonging to the same job, comprising: means for receiving the centeringcharacteristics and the geometrical data acquired by optically measuringat least one of the two lenses of the job, and geometrically measuringat least one of the two lenses of the job, and calculation means forreconciling the centering characteristics and the geometrical data ofone of the two lenses with the centering characteristics and geometricaldata of the other of the two lenses for both lenses of the jobconsidered together, and for delivering as a function of the result ofthe reconciliation and information relating to the morphology of theuser and a selected optical frame, a signal confirming or refusing saidjob.
 8. The method according to claim 2, including storing in memoryinformation relating both to the morphology of the user and to the shapeof the selected frame, and comparing said information with the centeringcharacteristics and the geometrical data of one and/or the other of thetwo lenses of the job.
 9. The method according to claim 1, in which thegeometrical measurement of said lens comprises a first measurement stepprior to said lens being blocked, during which said lens is measuredaround the outline desired for its mounting.
 10. The method according toclaim 2, in which the geometrical measurement of said lens comprises afirst measurement step prior to said lens being blocked, during whichsaid lens is measured around the outline desired for its mounting. 11.The method according to claim 3, in which the geometrical measurement ofsaid lens comprises a first measurement step prior to said lens beingblocked, during which said lens is measured around the outline desiredfor its mounting.
 12. The method according to claim 4, in which thegeometrical measurement of said lens comprises a first measurement stepprior to said lens being blocked, during which said lens is measuredaround the outline desired for its mounting.
 13. The method according toclaim 2, in which the geometrical measurement of said lens comprises asecond measurement step after said lens has been blocked on thecutting-out means, during which said lens is measured around the outlinedesired for its mounting.
 14. The method according to claim 3, in whichthe geometrical measure of said lens comprises a second measurement stepafter said lens has been blocked on the cutting-out means, during whichsaid lens is measured around the outline desired for its mounting. 15.The device according to claim 7, including memory means for storinginformation relating to the morphology of the user and to the shape ofthe selected frame.
 16. The device according to claim 7, the devicecomprising: cutting-out (6) for cutting said lens to shape; and transfermeans (2,7) for transferring said lens, the transfer means beingarranged to transfer said ophthalmic lens between at least two distinctpositions, including a measurement position presenting said lens inregister with the optical measurement means (5), and a cutting-outposition for cutting said lens to shape on the cutting-out means (6); inwhich the electronic and computer system (100) is operable: to controlthe transfer means, optical measurement means, and the geometricalmeasurement means together so that both lenses of the job are initiallyprocessed by the optical measurement means and by the geometricalmeasurement means, and to receive and store from the optical measurementmeans and the geometrical measurement means centering characteristicsand geometrical data; and if the job is confirmed, to control thetransfer means and the cutting-out means to proceed with cutting each ofthe two lenses of the job to shape, or if the job is refused, to stopthe preparation of both lenses of the job.